i used the rent compressor tool from autozone, and it worked perfectly fine. so i kept it. i think it was a good 35 bucks.

 

I spent $40 shipped on the one I bought, 75.5mm. No issues sliding my pistons, rings and rods in. Worked like a charm. Now I'll sell it, used, for about half what I paid. Or loan it out to fellow D-series rebuilders.