I have a 6.5-270 WSM that I'm going to use on a Prong Horn hunt this year. I like the Berger bullets, my choice is the 135 gr. Classic Hunter, 140 gr. EOL Elite Hunter, 156 gr. EOL Elite Hunter
My longest kill shot so far is 850 yards with my 7-300 Norma with the 195 Berger on Elk, I like heavy bullets, but the 156 gr. may be over kill
Not sure if you're looking for options or just want a pick of the one's you mentioned (any of those will do just fine).
Antelope are not particularily tough to tip over, we've shot 90% of ours with a plain Jane 700/ 22/250 with 55's and 60's. Tough to beat this combo.
As for your 6.5 WSM I'd take a quick look at any you mentioned and or would go with the 120 NBT, 129 Horn SP , 130 Sierra HPBT and a host of others. Tough to pick a bad one really!