In my exactly one year of reloading, I've used the following powders for my 69 gr. SMK's:
Varget - 24.0 to 25.0 gr. I have several batches, which I steadily increased, and I have no intentions of going further - I get great accuracy from the 25.0 gr loads, and really good accuracy from the 24.2, and 24.5 gr. loads.
IMR 4895 - I had initially bought two different powder types, and gave this stuff a try.
I had some phenomenal (to me anyhow) shooting using 22.7 gr. of 4895. 3 shot strings touching each other, at 100 yards, and covered up by a US Quarter at 150 yards. These are from two sandbag rests, and not quite rapid fire, but not the cooling down/cleaning in between each shot either.
The rifles used were:
My old reliable 16" Rock River Arms Elite Car A4, My project rifle I built for my son which is an 18" Larue Stealth Sniper upper on a Tactical Innovations lower, and my Steyr Jeff Cooper Scout rifle. The COL were at 2.260", and I used pre-primed Remington cases in the Varget and 4895, and just the Varget in some Lake City once fired cases with a CCI 400 primer. The Remington pre-primed cases provided better overall accuracy, possibly because they were brand new, or I haven't developed great case prep skills yet. I'm still trying to learn this art myself. I hope the info is useful to you - have fun and stay safe.
-tc