I think I figured it out: the easiest / best method for anybody who comes across this, *thanks to shonumi & jhonn:
Start here-> ISO -> Trim ISO in GameCube ISO Tool -> Compress trimmed ISO to GCZ in Dolphin -> GCZ file <- End Here!!
Here is an example how much I was able to compress a GameCube called 4 x 4 Evo 2:
ISO: 1.36GB / 1,392MB -> Trimmed ISO: 552MB -> Trimmed ISO compressed to GCZ: 264 MB !!!!
THAT IS 81% savings in space/mb Hell yeah!!!
So far my test show no flaws in game performance....
Start here-> ISO -> Trim ISO in GameCube ISO Tool -> Compress trimmed ISO to GCZ in Dolphin -> GCZ file <- End Here!!
Here is an example how much I was able to compress a GameCube called 4 x 4 Evo 2:
ISO: 1.36GB / 1,392MB -> Trimmed ISO: 552MB -> Trimmed ISO compressed to GCZ: 264 MB !!!!
THAT IS 81% savings in space/mb Hell yeah!!!
So far my test show no flaws in game performance....