wrt the font, firefly has font choices. I think it would be good to have custom controls if possible. I guess it depends on the end user as to whether standardization is desirable. As well as colorful buttons, I would have an interest in the possibility of text or list boxes, with integrated labels. Of course, this all could be added later, provided allowances were made early in your development. I'm not sure about defaults. Whether they should be simple, so that a quick and dirty? solution can be made, then tart it up afterwards, or spend time in initial micro programming the detailed appearance, and delay the completion of the answer. I'm tending towards initial simplicity, almost to the extent of having a standard size for a default button, just specify location and text. But then, a fully design-able button could have suitable defaults to achieve the same simplicity of use, and allow adjustments later on. I guess, from your point of view, writing the code to generate all this, it would probably be simpler to only create the basic features.
Anyway, fwiw, the buttons work ok, as do the labels as far as I can tell. Looking forward to text boxes, maybe options and lists, then I can try my next project.