I quit the last 3 bands I was in because of the same problem. I was trying the same things you are doing. It seemed childish to me to practice so friggin loud. The guys response in one band was "We all ride Harleys,...our ears are shot anyways". So..I guess they didn't care if they went totally deaf. Idiots. The best band I was ever in was during the 80s. We sat around a table with headphones and our instruments and practiced. We would do a live rehearsal on a rented soundstage. Everything fell in line. Just like when we were sitting around that table. And... the live rehearsals were FUN, Because everybody has a financial stake in it... Everybody gave 100%. It was awesome.