A23 is safe, don't confuse it with nearby A21 which is not. E15 and E17 are both safe also. All the other A,C,D,E checkpoints have MMW. Not sure about B.

The whole airport is connected airside, so you can use any checkpoint, then ride the skylink train. It's rare to see much of a line at any of the checkpoints.

If your AA flight leaves out of A or C, then A23 is your best bet. If you leave out of D, then E17 may be a bit closer.

FWIW, all the non-WTMD scanners at DFW are MMW with the new "gumby" imaging software. No Backscatter.