RE: Different Wheels F/R?
pretty much in the 1:10 drifting you're going to want to have the same compounds all around for the reasons stated above you'll spin.
in 1:1 im assuming different tires are used to help with grip (supras RWD grippier tires in the back to help hookup with the ground)
i think thats it.
just stick with the same compound all around and you'll be happy with results.