Compression test info

Just joined the site. Used the search key to try and find this info but only found parts of it. I am doing the famous "Ghetto compression test" on a 94 RX7. I know about the finger over the hole trick but does anyone know the actual gauge specs? I am told that you take the schraeder valve out of a regular compression gauge and watch the spikes as someone is turning the engine over. Was also told that N/A engine specs are around 85 lbs or beter if they are good. I need to know the specs for the 13BREW. I also have a 93 R1 and, though I have been told that the engines are the same and will bolt right in, I wanted to check here.

Thanks for any info that anyone can give me on this.