Shorter version. Ignore disc based methods and go for USB.
This gets to be odd. The earlier models of wii had chips added at various points that made it run copied discs. These ran at 6x DVD speed (the 360 is 12X unless you hacked it not to be, USB is north of that under normal conditions and going on about 20x at theoretical best).
Some earlier softmods and a few of the "cable chips" ran at 3x DVD speed but the softmod loaders made lots of effort to mask this difference, they did pretty well too.
The 3x speed command that was used was removed from newer DVD models which shipped with newer wiis, I also think people basically gave up on chipping the Wii.
Other cable chips that actually emulated the DVD drive (and read a USB instead) loaded it at 6x I believe and maybe even higher, certainly with the added bonus of lower seek times.
You need a chip or softmod with softmod capable DVD drive to run copied discs. If you made a 1:1 clone I guess it would work but you can not make a 1:1 clone without serious toys (as in DVD press, only Datel ever really did that). Burn speed has been something of a non thing since we all got DVD burners with buffer underrun protection (not sure when that happened but some point in the PS1 era would be a good bet there). If you use good media and do not have a crazy fragmented or active drive when burning it really should not matter. The only reasons to slow down are for a dodgy DVD burner, bad discs or a hard drive that can not pipe it to it fast enough.
All that said everybody uses with USB loaders or SD cards to load games these days. These run faster than even the 6x stock speed which is all sorts of good. On top of this newer models of Wii can not be chipped or even made to use the softmod options for 3x speed.