You can become a master if you just leave them on the research table all the time. I've got all mine at expert and a few masters and I'm trying to get a genius at the moment, so just do what I did and wait.
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All you have to do is keep them building for like a whole day, and it will probably have you as a master builder when you get back on.
Try having them repair all of the huts. Then when that's done, you can keep dragging them to the hut without flowers to "fix it".