My BH loop is improving at a solid pace, I think what helped the most is being able to adjust the starting racket position relative to the ball much better. For the FH I'm working on further reducing the amount of sidespin. There's still a little bit right now, which isn't much of an issue in game anymore, but it does make it much harder for me to loop half-long balls down the line. Not that of a big deal at my level, but being a perfectionist I'd like to fix that. My coach tells me it should also help with contact consistency overall, though it's probably more limited by a myriad of other things right now.
I recorded some of my BH loops from a side view angle, which showed that I still have limited forward lean, which in turn limits how much my elbow can move forward during loops since I don't have any space to move it back. I think what happened is that I found that too much forward lean wasn't working for my FH, so I adopted a smaller change than previously intended. After watching some pro videos, I realized that they actually adjust their lean based on whether it's FH or BH. They stand more upright for FH shots, and lean forward more for BH shots. I guess I should do that too instead of trying to use the same lean for both sides.
Also I tried out Zyre on the BH of a FZD. Man it's rocket lol. I did a bit of comp with my current setup as well as a Q968 with LAC on the BH side, the FZD/Zyre combo is a certifiable rocket, although on the higher end it didn't feel particularly different from the Q968/LAC combo. The somewhat surprising thing about Zyre is that despite the non-tacky topsheet, it feels more like D09c than D05. D05 despite having a softer sponge (and also thinner than Zyre) feels difficult to hit into and has low dwell. Zyre feels like it has decent dwell, and lower throw like D09c. In regular loops it really just feels like a faster D09c. It feels different with 1) full power loops where you start feeling the lack of dwell relative to the D09c, and 2) brush loops where you need to be more decisive and have more acceleration to grab the ball.
What's most interesting to me is that I kinda like it more on the FH side. I just need to shorten my swing a bit, and it becomes quite easy to play with. I make good acceleration when I brush loop on the FH side, and smaller strokes is an easy adjustment as my body habitus and physical strengths favor explosiveness over powerful large swings. I couldn't tolerate the D05's bounciness and lack of dwell, but the Zyre actually felt quite right! Umm a lot to think about for sure.