Steve...just to confuse the deal. Otherwise, you'll be asking again.
Yeah, pretty much as you asked on your last post...except...
You don't want the motor firing off at '0' TDC. 10 degrees before TDC probably closer.
On TDC compression stroke, yeah, both valves will be closed. That's just a general deal, tossing in what cam, the shape of valve train, blah, blah.
Once you find #1 TDC compression stroke...then back the motor reverse rotation by hand, going past 10 degrees BTDC. That takes out any slack in the timing chain. Then, in the correct rotation, bring the timing mark up to 10 degrees BTDC, or where ever you want the initial timing set. (Damn, takes longer to type this, than doing it!)
Once that is set, check your distributor stuff. Pull the cap, and look at which plug wire the rotor is pointing. Doesn't matter if you have a point-type, or electronic, but look at point where the dist. cam fires to #1 plug. If point-type, it's the instant the cam (breaks) open the points.
Simply rotate the dist housing, until the dist. cam is 'making the spark'. That sets your initial timing, fairly close to the correct timing. Then, looking at the rotor, and it's rotation, it should just be coming to the #1 plug wire.
As you say, your vacuum advance, in a position where nothing is in the way, for any adjustment.
Whole lot easier, than all the noise! Have fun!!