Pattern it on paper at 10 yards out of your gun and see what you get. Any buckshot load that will keep all its pellets on a sheet of notebook paper at that range should work.
If it can't manage that, I'd find a load that could.
Mindset - Skillset - Toolset. In that order!
Attitude and skill will get you through times of no gear, better than gear will get you through times of no attitude and no skill.