One thing to consider. Open guns are different from other division guns.
One shooter might recommend AutoComp but that doesn't mean you will have the same results when used in your open gun.
Comp/Port configuration, reciprocating mass dynamics, etc. are some of the factors that affect perceived recoil.
Try a little first, then buy some more if you like it. Load development can be costly if done in haste.
Another thing to consider is that even the most expensive powder (VV 3n38/ VV N105) are still cost-acceptable in comparison to bullet cost.
On my last calculation, powder cost (3N38) is still the cheapest among the components.
My 2 cent