Honestly I doubt there is much to choose between the 6.5's. I've had a .260 for quite some time and it is outstanding with 140 JLK's over 42.5 H4350 but for a recent build I went with the 6.5-47 since brass is now available from Lapua, the case uses small (magnum) primers and the case life promises to be exceptional. So far with 123 and 139 Scenars the 6.5-47 is a sub half minute cartridge and appears easy to load for with no need (as yet) to trim brass.
I'm running a 22" jury barrel on a trued up Remington, in a McMillan a5, just getting into load development. The biggest problem I've encountered in two outings is that I had to push the targets back to 200yds to see any differences in groups. I'm using berger 130 ar hybrid, cci450 primers, and varget. 36.5gr and 37.5gr show great promise. At 200yds 36.5 of varget gave me a half inch (prone off bipod) aka 0.26 moa. 37.5gr I pulled the fifth shot, if just felt wrong, but the other 4 were one hole total group was still under a half minute.
Loaded more up at those two loads to investigate and can't get them to shoot a half inch at a hundred... I keep getting 0.3, 0.4... Closest I could get to a half inch was 0.47 ... Never had such a hard time getting that mythical 0.5moa... Maybe if I take a Dremel to the crown?