The first question that comes to my mind is "Why do you want to go with the minimum number of spokes on a commuter wheel?" I mean, what are you trying to accomplish? Is there some kind of bonus for making it to work three seconds faster?

At your weight, with those relatively strong rims, 20 or 24 spokes will probably work fine. The wheels will probably need rebuilding at shorter intervals than they would with 32 spokes, and things like pot holes will be somewhat more likely to cause problems, but that may not be an issue for you. So if it's really important to you to delete a few spokes, knock yourself out. What you hope to gain from that deletion, though, is utterly beyond me.