I installed it to my OS4 emulation and installing was even slower than copying it to RAM.
It seemed to run okay after. I did have a freeze but it was only when downloading it and it invalidated my HDD image and kept making it freeze on boot. Never did that before. But I'm running FS-UAE. Maybe latest has a bug that freezes OS4.
So can confirm the corruption on 8 bit. It seems to change the palette but doesn't restore it when you quit. There is also some other bug. I tried to change screenmode back but it kept closing and reopening the screen and complaining about windows. I think this is a recent bug in the whole system as I've seen it on real hardware like X1000. For fun, after palette corruption, open ScreenMode for a funny effect.
So I have a RGB16 bit mode set in P4 mode. You may have to see if both UAE and P4 can be added as cards. Then see if you can run CodeBench on P4 screen only. If not use 16 but mode.
I tried to add UAE as graphic card but it didn't show up. This maybe because I'm using FS-UAE and it has presets for OS4. It also lacks support that WinUAE has like adding folder drives, so internal hooks aren't fully supported like in WinUAE, which could explain why UAEGFX won't work with my OS4.