Re: 260
It seems like a mismatch, pairing a lighter bullet with a slower powder. This is not a bad thing, but it generally means you'll run out of case capacity before you reach peak acceptable pressures and velocities. I'd either go with a heavier bullet, or a faster powder (with H-4350 being the slowest I'd use for the 123). Varget may be a bit fast for the .260 and 123's, and 39gr seems to agree with what I'd be considering max. H4350 is OK for .260, with 47-49gr being OK for the 95gr, and 42-44.5 being max with 140's.
Greg