80 and 60 percent?
In principle thats how its working.
Stick to the USB loading guide to partition your drive properly and set up a fat partition next to your wbfs game partition.
But as you likely won't be able to keep all games on your drive when partitioning you can also decide to have your complete drive in fat32 format, see the guide linked below.
I like WiiMC more than Mplayer
Maybe stop by in the Introduction section as well to say Hello.
Good luck for whichever you decide, further questions would go in one of the guides.
Usb loading - FAT32