57 has been required for few games, such as Call of duty, just dance, (and I never remember the other ones)
56 is only needed for Spiro (and not for the game, but for the USB Portal accessory detection only, the game works fine without it if you use base57), I don't know any other games requiring IOS56 but I don't play them, I don't know all games.
base58 is special, as it already contains USB2.0 driver from nintendo, it's not using cIOS open source USB driver (which is not that good in fact), and keep using the USB2.0 from nintendo.
having the official USB driver from nintendo, it has more compatibility with hardware, but IOS58's other features are less compatible with games not requiring that IOS.
a lot of games officially require IOS 36 or 38. rarely they require IOS58.
some games officially require IOS57, which probably has some specific feature, and that's why they don't work on other base.
Just install base57 in slot249, and 56 in 250
or
install 56 in 249, 57 in 250, and in the loader tell it to use slot250 to use base57 by default.
only set a game to base56 if it doesn't work with base57
base 58 is probably never really needed. it can be used as rescue, if nothing else works.
Alright, so when you said a "lot of games officially require IOS 36 or 38" . rarely they require IOS58, I have to assume that those games requering IOS 36 or 38 should work fine with IOS 56? Is this correct?
Thanks