I know that all rifles are different, but I've had the best luck with H4350 in the 260 Rem. It gives good velocities, and is very temperature stable too.
Another thing to consider is that Reloader 19 may be just a little on the slow side for the 130 gr. bullets. I did alot of testing with IMR 4831 and H4831, which has a burn rate similar to Reloader 19, and just was not impressed with the results. I think Reloader 17 may be a more suitable powder for the 260 Rem., if you are looking to stay with these powders.