Hello mitchgalea,
I think that correct approach would be to fix the bowl effect (if the surface should be more or less straight), then generate the orthomosaic in planar mode.
Bruteforce approach to fix the problem for this project is the following: copy adjusted F value to Initial tag in the Camera Calibration dialog, fix F value, manually add or subtract rather small value (from tens to couple of hundreds pixels) from that F value, then optimize the camera alignment and see, if the bowl-effect is reduced - repeat until it is fixed up to acceptable results. Then build mesh and generate orthomosaic in planar mode.