Southwester Dory Mizzen Location - Moving it farther back?

I'm strongly considering building this boat to sail.  I was wondering if any builder has modified the sail plan slightly by moving the mizzen farther back. I assume one would also use a smaller mizzen then.

My motivation is to open up more space in the boat, but I suspect this would affect the performance of the dory too, question of course is whether it causes more problems than it solves.