You would'nt want a 1:8 twist unless you planned on shooting heavy bullets at some very long distance.

I prefer to shoot 50-55gr bullets out of .224" rifles, especially for coyotes.

I also prefer the 223, as you can load 1.5 223 rds for every one 22-250 round.

My go-to varmint rig is a 243 (coyotes), and my go-to smaller sized varmint gun is a 223.