if the imprint goes on the butt, just make sure the art is setup properly and make sure you and your customer are aware of the issues with the seam in the center - if there are any (shoot your screen upside down) - gotta feed the panties from the top.
use a 10-12 inch pallet - more than enough for all sizes
If design goes on thigh, then you got to use smaller pallet - 3.5 to 6 inches - shoot your screen the normal way