Let me also say that I recommend trying MIA-PTY-MIA for same-day turns. Plenty of flights in case something goes wrong. PTY has an Admirals Club, and arriving/departing pax are mixed. So, you can get off the inbound and walk straight to the AC to check in for the return.

You might run into the issue of the 1-hour check-in deadline if your inbound is late, but again, there are multiple daily flights (plus a weekly DFW nonstop).