Anybody run 16's in the back and 15's in the front?

I am trying to help my buddy Russ (The Cisco Kid) figure out what wheel/tire combo to put on his stude coupster.

He was going to run American Salt flat wheels and put 16's in the back and 15's in the front. The idea is to run tall skinny tires all around put a little smaller in the front for the rubber rake.

After looking in the coker catalog it looks like there aren't any tires that match from the 15's to the 16's.

On the back he was going to run 16 by 5.5 inch wide wheels and in the front 15 by 4 inch wide wheels.

I think the 7.50 16's may be a little too big looking on there so maybe a 6.50 16 and I was hoping to find him a 6.50 or 6.70 15 or so for the front that would match.....

So what are you running that looks good? Here is the unit in question if you haven't seen it.......

 

here are those exact tire sizes on my project-t