Ive been thinking about buying some rear paddle tires for when I go to the sand dunes. Just got me a set of used 8" douglas black label rims to use for my paddle tires. I have a fmf fatty exhaust, k & N filter, and newly rebuilt engine (all stock). What size of paddles should I get? Was looking at some 18 x 9.5 x 8 aerospeed tires or kenda gecko 20 x 11 x 8. Both are 8 paddle. Don't want the most expensive, but dont want the wrong size either. Im not out to compete, just to have fun. What do you all think??