Are you gonna skin and eat 'em? If so then I would think a good .22 would be the ticket. I can't comment on the .17's because I don't have one. I've heard that they are too much for squirrels, but in your situation I would think the .17's would do just fine with head shots and give you more range. Now, if you aren't gonna skin and eat 'em then just about any varmint round would do. I don't have a varmint rifle, but if I was in the market I'd give the .204 Ruger a serious look.