I think with Pattinson being chosen you need to lean in to his body type in terms of what suit you pick. Yes im sure he will pack on some muscle for the role but I just don't ever see him being a big burley guy so I would avoid putting him in suits like (The Dark Knight Returns Suit or The Arkham Suit) as it probably won't look as good as something more streamlined as he has more of an athletic build than a muscular one.
Based on that my top picks for the suit would be
1. Jim Lee's Hush Suit

It may be my absolute favorite Batsuit ever so it had to make the list, not only that but the use of the dark blue colouring could make for a different aesthetic look that we've previously seen from Batman on the big screen.
2. The Batman Noel Suit

This if done by the right costume designer could give most Batman fans the best of both worlds. You could blend the real world almost ready look of the Nolan trilogy suits with the drama of the Burton suit with the cape flowing over the shoulders.
3. The New 52 Suit (Only when drawn by Greg Capullo)

Overall I think this one has the sleekest design of the three and I think its the one that Pattison's frame would best suit the most as the thinner design is more optimal for an athletic built guy than a muscular one. I know he's going to go to the gym for this role but he's just not someone I ever see being bulky.