Whats up guys

I'm buyin a 95 MB w/ R2 mods and want to do a compression test on the car b4 i hand him over the $$$.

The has 85k on the clock but pettit had worked on ths car and the motor was rebuilt at 75k. My question is how can i do a compression test with a regular piston compression tester. I know the Mazda one would be ideal, but i dont think i will have time to get it over at a Dealership to get the compression done from them.

Can i and how can i do the compression with a regular tester. Also what harness or fuses do i have to take off in order to prep for the compression test

Thanks