hard cranking after warm

With the fitech, you rev the engine to around 2000rpm then look at the fitech handheld unit and see what the timing is reading, grab your timing light and turn the distributor until your timing matches with what the fitech is saying.
OK, I get it. (I think, LOL) Just be aware that the timing light only shows the damper mark against the timing mark on the timing cover. That counts on the damper and its mark being properly aligned with the engine's crankshaft. Old damper rings have been known to slip and no longer be properly aligned with the crank; the crank position is what you want your ignition timing to be truly aligned to. (And a 1970 and later damper and a pre-1970 timing cover will be waaay off.....)

That may not be any issue for this hard-hot-crank problem but IMHO you would be wise to check the damper and its mark's alignment to #1/#6 piston TDC so that you have a known good timing baseline as you tune this thing up.