I installed the new CIOS, does it matter if it was under revision "21011" I think it was, instead of the usual 65535? Everything seemed to work fine, although I only booted a couple games for testing. I already had my CIOS in the order you recommended (249 56, 250 57), unlike modern guides that tell you to go 249 57 and 250 56, so I am glad I don't have to swap them.
I tried the framebuffer option and yeah, the 16:9 forced games look less wide and a bit sharper, but I will need to look into it with more time. I tried both DKCR and Kirby's Return to Dreamland/Adventure Wii, and it made a difference in both. I will have to check on other 16:9 only games and 4:3 games, but the ones that mattered for me the most are the former.
Again, thanks for everything.