And that's assuming successfully taking a new province each turn with no buildup, or no saving. I think starting with 9 provinces imo is more like turn 12-14, depending on layout/cash. I'd usually be at around 7-9 mages by that point, although I might have 1 or 2 floating with the army depending on path.
I like the idea, although you might need to do forced start locs or is the game smart enough to buffer capitals?
I take that back, i love the idea
Might also work well with one of the pre-fabbed maps with nation separators and a DMZ... but the map would be a pain to create.