Well they have different sub species....I think alaska only has 1 variety......but i agree I'd go canada, I think some caribou hunting in alaska can be very tough! not that canada is much easier, but I do thik more chances....

I saw a late season rut hunt with helicopters on .....jim shockey's show, it was awesome, expensive though! but tons of huge bulls.

I think its the central barren ground that have the largest antlers......thats where I'd probably start.....pick the sub species you want I say and figure out wher eto go for that variety.