You have a very nice sketch Wade - DON'T MESS IT UP!!! For cryin' out loud! lol If you want to do a watercolor, do a watercolor. (Ask JC, he does watercolors I think.)
If anything, work some on the sketch. It's very nice, but might be worth spending more time on it to refine it. Especially with a geometric subject, it's more noticeable if lines aren't defined enough. I can see where it could benefit from working further on it, but DON'T PAINT over it and ruin it!! It's too nice a drawing to wreck it.