I admire that you make the effort to go a step beyond with a colored shirt, neck tie, suit jacket, etc. You obviously take a look in the mirror and a little pride in your appearance. I (and your audience members) surely appreciate it and could never accuse you of being lazy.
Black dominant can be a default born of lack of creativity and effort, or it can be fashionable. You are obviously much more the latter.
As for the "slimming effect" of black, well, if it makes you feel better, good. As has been said several times on this thread, it's more myth than fact. Big guy still gonna look big in black, but can arguably be more fun, entertaining, and big in other colors.