I am primarily a keelboat racer but thoroughly enjoy racing Flying Scots.  With respect to the Scot, a flat boat is a fast boat so these depowering recommendations will also help you even though we use them for racing.
First if you have older sails they may be harder to depower because a baggy sail holds a lot of power in the breeze.  Not suggesting that you must have crispy new racing sails but the adjustments below won’t as be effective the older the sail.
"I move the jib sheet blocks back" - Moving the fairleads all the way back will flatten the bottom of the jib and open the top leech which depowers the jib.  The sail area of the jib is small compared to the main so this adjustment alone would be hard to detect which is why you might not notice it.
Jib Halyard Tension – If you see scallops in the luff of the jib increase your jib halyard tension until they disappear.  This will also help depower the sail.
Cunningham - If possible rig a cunningham it will help move the draft of the main sail aft which is especially helpful if you have older sails.
Main Halyard Tension – Make sure you have a full hoist with a significant amount of main halyard tension, especially if you are unable to rig a cunningham.
"I'd love to hear thoughts on the vang" - Upwind with the vang on hard, it will flatten the main sail significantly depowering it, but without a cunningham to move the draft aft the effectiveness will be diminished.  Off the wind you would leave cunningham on and ease the vang so the boom may rise and provide the twist to open the top leech of the main sail depowering it.  It is not a static adjustment, vang on upwind depowers, vang on downwind powers up the sail so it must be eased.
“I crank on the outhaul as much as I can” – This flattens the foot of the sail depowering it but without cunningham and vang it is not as effective.
Centerboard - "Reefing from the bottom up" was a foreign concept to me when I started sailing a Scot, but it works.  Raising the centerboard decreases the lift it provides and it will noticeably flatten the boat.  Upwind you will slip and not point very well (ask any racer who forgot to put down their board at a leeward mark rounding). Depending on how breezy it is and how far you bring up the board, you may find it difficult to tack.  This is something you should practice to get a feel for.
Mast Rake – I recommend setting your rig to the specs your sailmaker recommends and leaving them there.
Hope this is helpful and interested to hear how it works out for you!  

My 2 cents...but consult your local Harry, Tyler/Carrie, Linton, Zeke or Brian Hayes or Ryan Lalmgrem or other rock stars for more clarity. They are hubs of information and they are all fast/highly competent.
IN FAVOR OF VANG: Vang does bend the mast and therefore flattens the sail...but it does this via tensioning the leech. If you had a backstay, you'd crank that on to bend the mast, but we don't have that...so we crank on the vang to bend the mast which flattens the sail. OK, great. The mast is bent and the sail is flatter. Now what.
The other benefit of cranking on the vang is it keeps the leech firm so when you ease the mainsheet in a puff, the firm leech stays firm, which drives the boat forward and upwind too (you can steer higher into the wind to feather quite a bit here...otherwise refered to as "carving up". Without vang/leech tension, the main goes bezerk (lots of twist as you mentioned) when you ease in big wind...and you enjoy very little "relief" from the heeling moment. The heeling continues, the boat slides to leeward, and the boat stops driving forward. It doesn't feel good at all. Brian Hayes calls this the "ugly dance". Zeke Horowitz also reminds us that when you have leech tension via vang, it keeps the rig (forestay) firm (which a baskstay would do, I think) which means your jib shape is stable and the groove is easier to find and maintain even when your main is eased substantially and/or you're banging into waves.
SOME NEGATIVES OF HARD VANGING: When you get to your personal limit (high teens and certainly in the 20's makes most of us very nervous), I would say yes...ease that doggone vang, spill some air and survive. If you don't, the mainsheet can be eased entirely, and the leech tension alone will keep the main sail trimmed in quite a bit, the leech stays firm, and all this can absolutely knock the boat onto its side. If you're in the 'ease the vang/spill air at the top' mode, I would seriously consider going back to the dock.
My mentor here at Lake Norman Commuity Sailing, Larry Vitez, who weights in at whopping 160 lbs advocates going out singlehanded or doublehanded with main only (no jib)...and the centerboard up substantially to alleviate weather helm (half way up, I think). Speaking of raising the board, Harry Carpenter gave a talk recently at a Great 48 where he said he also raises the board a bit when going upwind in big air to alleviate weather helm. So play with that. Harry also mentioned the importance of easing the jib a bit or the air coming off the jib shoots into the back of the main causing a huge amount of unhappiness on the backside of the main which moves the center of effort further aft, making the weather helm worse IE if the main is out in a big puff, the jib can and should be let out a few inches too.
DON'T FORGET: The vang gets tighter when you ease the main out because of the architecture of the boat. Heavy vanging upwind means you gotta ease that vang before you ease the main and head downwind or it'll break.
I've dumped the boat a few times in recent few years as I struggle to figure out out how to deal with heavy air. It aint fun dealing with a turtled boat. And it lalways leaves me gun shy for regattas to come. Hopefully my comments are of some help and/or a springboard for more comments by more experienced Scot sailors. If I've misquoted anyone, please be gentle...correct me.

If you really do not want to bother with installing a reef for those windy days then you can consider dropping the jib and raising the centerboard about 1/2 way. There will be weather helm on the tiller and you will need to make sure to have speed for coming about, but the boat will be much more manageable. Re-connect the jib halyard so that two wires will be supporting the mast from the front. I would however recommend a reef. The factory version is the delux way to go, but I have sailed without any problems with less hardware and less expense.  Ask the sailmaker to install a gromet at the foot of the sail near the outhaul and that will save you the cost of a pulley. Also I use a vee jam cleat for the reef line, located on the boom near the gooseneck.
 I hope this helps  Gabor Scot 3512

Someone said the cunningham moves the draft aft when applied....The cunningham when applied moves the draft forward not aft. The further the draft moves aft of the original design the slower and worse condition you will be in in high overpowering winds. Also when applied relatively hard in overpowering winds it helps open the leech up or twist it open high in the sail making the sail more forgiving.