340 Static Compression Numbers and Test Procedure

I can use a piston stop BUT haven’t pulled my heads YET lol. If I start to disassemble I might just start a full tear down and do it right. This guessing game of whats in there is driving me nuts.....
Piston stop I'm referring to requires no tear down. Pull plug from #1 cylinder, put the stop in place and adjust to contact piston a bit before TDC, 20-30 degrees and go from there.
I think this thread goes through it pretty well. probably videos on utube
How to find tdc