I've done the QR DOH-DFW numerous times ..connecting on separate PNR's..but I've never booked my AA flight fm DFW any earlier than 6pm.

in ten flights...I've never been late and a few times I was able to go via standby on an earlier flight.

several times I've had no luggage..other times I've had luggage to recheck again after customs at DFW. So obviously if u hv only carry on luggage and global entry ..quicker transit times

if u book one single ticket on QR..including the DFW in one ticket then I wudnt worry