I like the stance on your Cougar, as it is old school with the rear lifted. When I bought my KR back in 1981, it had 275 60 x 15 Comp TA's but with air shocks.
What front tire size are you running to get the forward rake? I use 215 70 x 15's as they are about the same diameter as the 255 60 x 15 rear tires.
Don
gt350bp