Do you see the irony in downgrading an IOS (a process which has caused bricks in the past due to older IOS builds being incompatible with newer hardware) in order to protect against a brick caused by downgrading?
If "almost every guide" recommends doing this, it just shows that the people writing these guides have no fucking idea what they're doing. Installing it into the IOS90 slot with a high version number is particularly stupid - there's no way of knowing how IOS90 will operate, it could be completely incompatible with IOS60 so when a new system menu arrives and calls an IOS90 specific command (which fails because it doesn't exist): instabrick.
"Yo dawg, we heard downgrading was dangerous so we downgraded your wii so you'd be safe when you downgraded your wii."
I don't dare argue with you but instead seek your knowledge. If you are referring to putting IOS60 into 70's or 80's slot, I don't see what the negative effects can be when no one has ever bricked from this and it can prevent korean wii's from getting the 003 error. Please fill me in.
It's an out of date IOS. That means there is no guarantee that it will run on current/newer hardware (or be compatible with things like newer peripherals or online components), just like wanky's old "safe" updaters that installed specific IOS versions that didn't run on the so called "LU64" wiis.
Saying "no one has ever bricked from this" does not mean it's safe, nobody ever got bricked by region changing a korean wii either until Error 003 came along.