I have TKC 80 front and typically a 908RR rear. It is a great combo for the dirt (except really loose sand or deep mud) and the combination is acceptable on the street - after the tires are worn in (100 miles or so). I definitely don't get to dragging my foot pegs on the street as the front tire let's go long before that.
I have found that I typically go edge to edge on the front and still have about 1/4 inch on each side of the rear tire when I ride on the street. That is pretty much opposite of what happens on my sport and street bikes.
I did find the limit the hard way and almost high sided. Got it back - but still crashed into a guard rail.