Re: Rl-10x Alliant powder?
Did you try the online resources that Alliant publishes? They're conservative, but will provide good starting points.
My dad uses it for very light bullets in the 22-250 (35gr Vmax) with decent success. The bullet is so small and the bearing surface so short that it's difficult to load well and it has a large jump to the rifling, which doesn't help accuracy.
It makes a mess of rodents at 25y though.