I personally dont like those case's. The GC can be very picky with media, about the only disc that works in atleast 95% on GC's are G04's. I use Traxdata branded G04's im lucky enough though to have a GC that also reads Mini Verbs.
What you could do is use G04 mini's assuming they work in yours but keep a backup on the game on a 12cm disc(ty or verbs are good). You can get about 3 GC backup iso's on one dvdr.
I would also sugguest using a pioneer drive for GC games if you have one.