Okay. I have a solution that works for me. With it I can achieve the 2PP match.
For me, the Enscape settings box for 2pp could not be checked. At all. So i did some experimenting. Here's my solution (which maybe others have already discovered a long time ago, but it's certainly not intuitive or apparent to me):
1. Do NOT engage Enscape sync just yet.
2. In SU establish your shot w/out 2PP
3. in Enscape, enable 2PP
4. Back in SU, enable 2PP
5. THEN sync.
To match the output sizes I get the SU and Enscape output sizes close. In Enscape you can choose the aspect ratio to sync as SCREEN. I open the smaller of the two in PS. Then I 'place embedded' the larger render in and it comes in exactly in the right spot (less the top and bottom difference that occurs from the difference in size).
You can also start with the larger, place the larger, and scale it. Boom!