Ruger's original Vaquero, usually now called the "old model Vaquero" in CAS circles (not Ruger's term) was made in both standard plow-handle and Bisley versions, and chambered for both .44 Mag and .45 Colt (along with some other smaller cartridges). This original Vaquero seems to be strong enough for heavy loads, certainly as strong as a Super Blackhawk since it's the same basic frame and cylinder sizes. I've not fired heavy loads in any of my Vaqueros, though, and the Super Blackhawk cylinder LENGTH is a factor compared to the Redhawk... so the old Vaquero has the same limitations. I'd suspect you can pick whichever cartridge you prefer; game won't notice difference.
Note there was also a Bisley Blackhawk, too, built on the Super Blackhawk frame size. Both chamberings, I think.
Ruger's New Vaquero -- or maybe they call it the New Model Vaquero, is smaller, roughly the same mid-size frame/cylinder as their original .357 from way back when. They do chamber that in .45 Colt, NOT in .44 Mag. I've heard there is (or soon will be) a special distributor's run chambered for .44 Special. This smaller New Vaqeruo is NOT/NOT suitable for heavy loads, per Ruger. And the standard grip frame is smaller enough that it'd hurt me. I think I've heard there is or might be a Bisley version, and that might be more acceptable... but I've not seen/felt one, if they exist.
I have loaded/fired 320-grain cast bullet loads from my Redhawk and from a previous Super Blackhawk. Cylinder length was an issue with the Blackhawk, so the loads were slightly different. This was using a boatload of W-296 or H-110 (same powders) with chronographed velocities in the 1200-1300 fps range (I'd have to look up my notes to get the exact figures). Probably shoot through trucks. I know from first-hand experience that a hard-cast 240-grain SWC at roughly 1250 fps will shoot completely through a scrawny Appalachian whitetail lengthwise... so heavy 320-grain bullets aren't usually required for anything less than one of our Eastern Appalachian Elephants, which of course are smaller than the African versions
Back to the original question, given sufficient handgun strength, the critters won't know the difference. Given the stronger Ruger revolvers (or Freedom Arms, for example), you can load to reasonably powerful levels on each.
Pick whatever you like.
-R44