Ok, thanks. So assuming I use an external mag, those little GPS units would do a reasonably good job? My main interest is just RTL and position hold, and even then I'm fine if they're just in the ballpark so to speak.
If I'd need to use a larger GPS, then the attraction of the mini board is somewhat reduced and I'd probably just go for the full size Revolution w/telem radio integrated - gain some size in the FC, but eliminate the need to carry a separate radio makes it a wash.
And on that mini board (common on Banggood), it has two ports, main and flexi, so I assume those could be used for the GPS and a mag, once the firmware supports it?
I'd love to see how small I could make a quad that still retains GPS functionality.