Was able to finally make it to the range yesterday. Not sure if this helps anyone. I'm still deciding whether or not to try the 75's.

Savage 10 Predator. This is what mine likes:

2.26 COAL
rem. 7 1/2 BR
69 SMK
25.3 gr. Varget @ about 2700 fps. (a little slow in my book)

Tried a mix yesterday came to this conclusion:

2.26 COAL
rem. 7 1/2 BR
69 SMK
25.2 gr. R-15 (one ragged hole) Chrono was down so unable to get velocity.

Roger, If you get your 75's to shot and are willing to share info I'd love to know. Eric