Your post worries me, as I'm flying from YYZ to CZM in September. We don't switch planes when we stop in DFW, so no worries there, but returning from CZM we have 1 hr 15 mins at DFW to grab our luggage, go through customs & immigration, security (AGAIN), check our luggage (AGAIN) and catch our connection to YYZ.
Ugh.
Christine