The pattern board is the only way to really know what your barrel likes. You implied that your barrel is set up for choke tubes, and if that's the case, you'll need to pattern different loads with different chokes to really answer your question. And IMHO it really is worth doing the work to find out what your gun likes.
Through the years I've found that getting the forcing cone extended and polished does more to help with patterning buckshot than anything else I've done to a barrel's interior other than adding choke. This seems especially true of larger buckshot like 00.
And if you can get your barrel to pattern with #1 buck, don't let anything happen to it. I've been looking for a barrel that will shoot it for more than 30 years and have yet to find one.
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.