Very interesting idea.
I usually trim mine back a little at a time, trying to get any excess off the tab. After shooting it for a little while, I hook the string, and mark the excess material with a marker, and trim. Be careful; it is easy to go too far and begin to touch the finger.
I also make my own from a sheet of cordovan. I take a cheap piece of material (any kind of leather), cut it, use it a few shots, and then begin to trim it. That way if I go too far I have not ruined my cordovan. Then I use the finished product as a pattern to see how much I can take off the cordovan.
Unless the tab is just crazy excessive, I would wonder it the porpoise is not coming from something else. It may sound silly, but I have a Matthews Genesis Pro that I matched a 1716 aluminum too by bare shafting it. It flies like a dart.
I am pretty sure you know this, but I would check for poor spine match, rest contact, nock set height etc.
I am not sure what all those initials stand for, but I assume you are instructing kids. What a cool thing. Kudos to you. You may affect the entire life direction of a young person.