So, I have figured this out; however, it can be quite touchy and depending on unknown factors, you may need to delete constraints and put them back. But here's what I found works:
Contraints: CenterY on parent view (Priority 1000) CenterX on parent view (Priority 1000) Width = Height of view (Priority 1000) Leading to parent view => the amount you want at minimum (Priority 900) Trailing to parent view = the amount you want at minimum (Priority 700) - I have stuck with same as leading Top to parent view => the amount you want at minimum (Priority 900) Bottom to parent view = the amount you wan at minimum (Priority 700) - I have stuck with same as Top Width = some amount that is less than the parent view size in the smallest device supported (Priority 500) Height = same as Width (Priority 500)
I usually start with CenterY and CenterX at the same time, then do the other six at the same time.
I've been having good luck with this on a number of Apps recently. It took quite a while to get there, but seems to work well now.
Thanks.