James,
I would check with Harry before lifting the Scot with anything other than the lifting bridle.  I suspect neither the bow handle nor the transom rings would safely support the weight.  Moreover you need a way to lower the board while the boat is suspended.  Not a good idea.
The best way to inspect the centerboard is to remove it.  Launch the Scot and when at the dock, lower the board.  Attach a loop of wire or rope around the centerboard lifting roller.  Unsecure the centerboard wire/hauling line and remove it from the lifting roller.  Do not remove the centerboard/well rollers.  Use the loop of wire/rope to lift the board out of the well.  It's heavy so have at least one other helper.
Good luck.

I have used Glenn's method to take out the board.  The second method seems like a lot of work.  I have also launched the boat onto the grass, raised the mast and then used a rope to pull the boat over.  You tie the line just above the shrouds on the mast.  I then use a 50 lb sandbag on the top of the mast to hold the boat on its side.
This allows you to check out the board, and work on the bottom, or change the gasket if needed.  If you are going to do the work, you may as well fix all the variables while you can get to them.
Removing the board is tricky on its side, as it will wedge in the trunk.  You need two people to remove it easily.  You only need it down part way to fix any dings, since they are usually in the leading edge.  That said it is easier to work on it out of the boat.  Be careful not to "improve" the profile, as the factory profile is the only class-legal shape.
The bow eye and stern rings are not meant to hold the weight of the boat.  Don't get under it.
Phil

To get the boat back on the trailer, i always launch it onto a slightly convex hump in my yard.  I slide it off onto a heavy plastic tarp, which i put soapy water on.  It's just like launching into water, but you have to steady the boat side to side, so it doesn't bump the trailer and scratch.
Putting it back on is easy.  You get a helper to sit on the transom, while you put a 4X4 block, with a throwable cushion between the block and the boat, under the bow.  This lifts the bow just a bit.  You then bring the empty trailer, without the car, and place the center roller under the bow centerline, and connect your winch strap.  The trailer tongue will be about 6 feet in the air.  Have a helper keep the boat steady and level, side to side.  Start cranking the boat onto the trailer, and be careful to keep it headed up the center rollers.  You can maneuver the trailer by moving the tongue left or right.  As the boat first begins to climb onto the trailer, the trailer is actually getting pulled under the boat, as the boat is stationary.  As the boat clears the ground, you will reach a balance point where the tongue will come down.  If you crank too fast, it will come down too fast, as the boat goes past its tipping point.  Crank it up tight, and you have it.
Slow and steady wins the race, as getting it straight on the trailer is important.
Have fun.