Which 2ltr do I keep?, Leak down test says keep them both!--Can't be right Options

[computers4kids]

Here's the deal...I have a 75 2ltr and a 76 2tr? I only need one...going to sell the other one. Both are FI. Supposedly the 76 was just rebuilt...actually I would call it freshened-up i.e. new rings.

I did a leak down test on the 76 and all cylinders were about 3-5 % leakage...OK, then I do the 75 and it has even less leakage..NO WAY...that can't be right. They both can't be in that good of shape...must be doing the test wrong.

Am I doing this leak down correctly?
1) Bring piston to TDC
2) Air compressor is set to 100 PSI
3) throttle body open
4) Connect tester that has two guages
5) According to the directions I turn the knob cw (bottom of first gauge) until the guage on the right reads "0" (far right at end of yellow zone).
6) Leave at constant pressure and then watch the needle. Read the amount of leakage.
Does the numbers on the gauge on the left mean anything?

I know the motors are suppose to be warm, but I'm primarily looking for a differential between cylinders this should be OK test.

Question 1: Am I doing the test correctly?
Question 2: What else can I do to help decided which motor to keep?
No need to post a picture of either motor (unless you want)..they look pretty much identical. I'm leaning toward the 75 just because it looks like it has never been touched...not knowing what kind of job the mechanic did on the 76.
I need your advice!