Ah yes, I had a table do this. My bet is you are correct. It is possible for the table script to size the DMD. Here are the three lines you want to search for:
dmd_pos_x
dmd_pos_y
SetDisplayPosition

Just comment those out if they exist, and then see if you can size it.

Macro maybe (to switch to Portrait when PA launching, and switch back when done)? I've only been using VP, FP, and PBFX and not bothering with PA (especially since I can get all those tables in VP anyway), but something like this with a macro for using the hotkey might solve the issue:
http://www.softpedia.com/get/Tweak/Video-Tweak/iRotate.shtml

They've announced they are able to do the AC/DC table without needing a Kickstarter.

http://www.pinballarcade.com/News/