Should be possible, just ‘invent’ some technique, mainly meant for standardizing.
Something along the lines of:
1) Obtain full erection
2) Hang something which can be filled up on penis
3) Fill it up(material doesn’t matter) until your erection stands parallel to the ground
4) Remove and weigh
You will have some problems, since you aren’t measuring the penis itself, but the amount of weight it can hold.
You will probably run into a variation of the leverage law (length of arm * mass), but that’s ok, since we measure our BPEL and therefore can divide the mass by the length of the arm.
This will give your “weight” per inch of penis-length, automatically standardizing it.
Of course, these measurements don’t measure your penis weight, but you can say something about the EQ or more roughly taken, your ‘lifting ability’.
It would end up being something that could give PE a bit more of science, whereas you will get certain numbers that correspond with a (good, reasonable, bad, etc) EQ or lifting ability.
This might result in some nice values used for reference for starters.