Thanks for the feedback.
I'm working my way through it. I've come up with a simple(ish) formula for map dimensions. Essentially if you allow each province a 120 x 120 pixel dimension, you simply multiply the number of provinces by 120 squared to get your total pixels. To make a square map you just take the square root of this total; or you can set an arbitary width - divide the total pixels by this amount to get the height. So the the formula is
w x h = p x (120 x 120).
With Fiddle Prov%, is it a logrithmic scale, linear scale, or some other formula. I'm wondering if 100 in the builder is really 50% or some other figure?
I'll post next draft again soon.