Reloader 17 was the first powder I tried in the 6.5-284 but it is way too fast for bullets over 100 grs in the WSM. It will not fill to 75% with 130 gr bullets. I consider that dangerous. I would think that Reloader 17 would be outstanding in the Creedmore or 260 Remington with the mid range bullets.
I have tried Superperformance in both the 6.5-284 and 6.5 WSM. I will say I like the powder in the 6mm Remington with 90 gr Accubonds. I have not found another niche for Superperformance where I was rewarded with either velocity or consistency. The local Cabela's salesman at the reloading counter swears he has gotten the amazing velocity listed on the container for Superperfomance in the 300 WSM
with 150 gr bullets. I have tried several primers with it. I like 210Ms in the 6mm Rem.