I have been reloading for the 26 Nosler for three years and have tried just about every powder out there. I shoot a Browning Long Range Hunter 26" stainless with an 8 twist.
My gun loves the Berger 140 grain Elite Hunters and the best powder I have found for my loads is the Vihtavuori N570. I worked up a load from 76 grains to 79 where I started seeing the slight first pressure signs. Best accuracy load for me was 77.5 grains.... 1/2 moa at 200 yard zero. Coal with these bullets is 3.465 and I am 15 thous off the lands. These are hybrid bullets so seating depth is less of an issue. I hope you find this helpful ... I share your frustration with getting load data for the 26 Nosler... it is so slow coming other than from Nosler and even with them its scant at best.