Nice work. I like the thought you put behind what you are doing and the fact you are getting it done.
A couple things I would suggest, and by all means dismiss them if you think they are off base, is to pattern your curls around high reps rather than lower reps and to not think of high bar and low bar as more upright or less upright.
Your biceps will tear more easily the higher you are in their ability to contract. They will take a serious amount of abuse daily and with hi reps, but if you enter a curl contest, they will tear like wet tissue towards the end of the contest.
They might be slow to "grow" but they are getting stronger I guarantee it with high reps. Very few strong people do low rep curls if any as I can't think of any. Very many strong people do high rep curls regularly and are very big and strong. Just sayin'.
As for high bar and low bar, this has to do with your body's leverages, not anything someone has tried to sell you. I used to think high bar classic style was the only way to go to show off pure body strength, not some powerlifting cheating style that helped you look stronger than you were.
Well guess what, I could not stay upright hi bar nor hit depth consistently. Now I low bar and hit depth every time and stay more upright to boot. Turns out for me where I set my chest is far more important than where the bar is. Hi bar I can't expand my chest as much, but low bar I can and when your chest is out and proud, you are in your best position to squat.
Not an expert, just saying what I believe. I hope you find your own perfect form. No one is the same as anyone else.
I am Anton Zdravko Martin!
Best meet lifts: Sq 150 Kg (330 lb), Bench 120 Kg (264), DL 160 (352) @89 Kg (197)
Best gym lifts: Sq 375, Bench 280 (pause), DL 385 @205 or less
Goals beyond my wildest dreams, 600 Kg raw total, 200/160/240
Hack away at anything which isn't essential. Do what you love, and do it often. Fazc.
Everything competes for recovery so more assistance is not always the best idea. miked96