I've been following this thread for a while and this round shows a lot of promise. It would be sweet if it gains enough traction to warrant a run of brass. Congrats GA on a fine platform.
Interestingly I read an article by Lane Pearce in the August 2013 copy of Shooting Times where he describes his experience with the 6.5 SAUM wildcat he named the ".264 Rocket". I couldn't find a link to the article on the net, but I thought some of you may be interested in his published load data. Looks like most of his testing was based more on traditional hunting bullets. It will be hard pressed to improve on most of your H1000 and 130 VLD loads, but the more data the better. It may give you some ideas on other types of powders that might work, if H1000 can not be had.
All of his data is based on a Lothar-Walther 24" barrel, Rem 7 SAUM brass necked downed, not turned, and CCI 250 primers (except the 120 Swift and 129 Interlock loads, where he doesn't specify what primer he used)
Barnes 120 TSX, RL 22, 61.5 grains, 3407 fps
Berger 120 Target, IMR-7828 ssc, 61.5 grains, 3324 fps
Swift 120 A frame, IMR-7828, 62.5 grains, 3350 fps
Nosler 125 Partition, H1000, 65.5 grains, 3300 fps
Nosler 125 Partition, IMR-7828, 62.5 grains, 3326 fps
Hornady 129 Interlock, IMR-7828 ssc, 62.0 grains, 3243 fps
Barnes 130 TSX flat base, RL 22, 61.0 grains, 3277 fps
Hornady 140 SST, VVN165, 60.0 grains, 3049 fps
Remington 140 CL, IMR 7828, 61.0 grains, 3073
(Note, based on his 100 yard accuracy report, the most accurate was the 125 partition with the H1000. I guess even he found H1000 as the go to powder.)