Should be a good low recoil combo. I use the light high velicity 22 wmrs in my 22 mag and prefer the win black box supremes first and the Remington premeirs vmax's seconds. The winchesters are more accurate out of both my 22 mags and seem to explode at lower velocities where the vmax just cuts right through (shooting apples at long range is a blast!)
On the 20 gauge I wouldn't use (don't like) 0 or 00 buck. You'll have to check on the 20 but I believe a 12 gauge 2 3/4" 00 buckshot has 9 pellets, 3" has 13 or 14, and the 3.5" has 18 pellets. I used the federal 3.5" 00 buck for a couple of years and really got soured on it. I imagine a 3" 20 gauge would have between 6 and 9 00 buck pellets. Even at .33 cal per ball, I don't like those numbers on a coyote.
Instead I'd get #4 buckshot. You'll have a couple dozen .22 cal pellets headed downrange. I much better like those odds.
I've been looking at the 223/12 gauge combo. Please report back yours shoots!!!
later,
scruffy