I also have a 20ga pump as part of my HD setup. I can tell you that I am not concerned with 5+1. That is not to say that I don't have a backup plan if things begin to go poorly. Things can go South no matter how many rounds you have available. Things fail, guns fail, nerves fail.. I consider it a pretty good idea to have at least a backup plan. Overall, I think your SA-20 is a darn good gun and if you are accustomed to it, that adds another point in your favor. If it were me, I would consider your situation to be reasonably met. If you told me it was a single shot 410, I would encourage an upgrade for a worse case scenario.