I'd like to second this thought -- on each of the occasions that my thoughts turned to "hey, I can just do a little bit of paid development work part-time while

I'd like to second this thought -- on each of the occasions that my thoughts turned to "hey, I can just do a little bit of paid development work part-time while I work on my own stuff!", that "part-time" gig somehow managed to take over my entire day/week. And so all that extra time I had imagined I would be spending productively working on my own stuff mysteriously evaporated, because my paid work was taking up all of my headspace. "Brain-dead" work, on the other hand, tends to make me _more_ productive when I sit down to design or develop something. So there's probably a continuum effect here. My recommendation to the original poster is to find the _easiest_ and most menial job that still meets the requirements of your visa, whatever that may be.