Side AO is fantastic for adjusting parallax on-the-fly in the field. Mildots are equally valuable. 30mm tubes have a LCF, but don't really offer any tangible benefits for varminting. Primarily, they're designed to offer more elevation than 1" tubes - which is a non issue inside 600 yards.
I like the Bushnell 4200 6-24x40AO and the Leupold VX-3 'long range target' series