I've got 28" Zillas skinny in front wide on back on my 12' brute. Love it. There great in mud good on trails and fields and still feels like nothing there when steering(I've got eps) only down side they aren't to good for backing out of mud or snow. They are also very good in snow
your choice, pure mud tires are non forgiving on axles or diffs. you will be buying new axles. as suggested the zilla tires are a very good all round compromise, lighter, softer rubber so the tread will bend a bit, and run about an inch short on rated height. definitly not the best rocky terain tire, but will work. bigger tires will require clutch work and other mods to follow. the suds buds seem to all like the zilla tires, and they usually give them a work out.
I prefer skinny wides myself. Originally went the xtr route and they just didn't cut it playing in the mud. If you want to ride aggressive mud go with a mud tire. In the 28 inch size I like the silverbacks over the outlaws and as was said you might have to look for some clutching.