Finding Top Dead Center (w/ Piston Stop) - HELP

Seems to me you can ignore compression stroke, both valves closed, etc. TDC on the crank is the same on compression or the top of the exhaust stroke.
Just use the piston stop and forget about which stroke it's on.

 

Here's a pic of one, very similar to what you came up with. The lock nut on top of the old spark plug makes the depth adjustable, for those pistons with the deep dish.

 

FWIW using the piston stop method (stopping at each side of piston travel) results in setting 0* at dead center, i.e. the center of the dwell.

 

Take out #1 plug turn it past tdc on the damper use a blow gun in the spark plug hole it you hear air coming out the carb it's on tdc exaust if it trys to roll the engine over it's on compression.

 

Being an old machinist I like the dial indicator, hard to mess anything up with it. Plus I have one.

 

If it's a running engine the dist rotor will be pointing at the #1 plug wire when in the vicinity of #1 comp/power TDC.

Damper "hasn;t slipped much"
If it has slipped AT ALL it is toast, and deadly. I'd at least put a white stripe from inner, across rubber, to the outer ring and if it shifts any more at all, replace it.