H1000 is my go-to powder for the .300 Win, currently I have 4 on the go. I've used it with 180, 190 and 200 grain bullets with excellent long range results. My "house load" that I use interchangeably between all of them is 80 grains of H1000, 180 Accubond or Ballistictip, Federal 215M and Norma brass. Thats about a grain under max in most books but its plenty warm. Velocity is right at 3050 with the 24" barrels and 3150 with the 26". Drop back 1 grain for the 190s and 2 grains for the 200s.
A couple of trivia items;
1) You will notice a distinct difference in recoil over your 4350 load.
2) H1000 got its name by being the 1000 yard powder for the .300.