It would have an increase over the .35 Remington, a fantastic strong and inexpensive case. SOme of the .35 cal. TC's have goofy throating and a re-chamber fixes that. I have a 8-3/8" old TC .357 Mag. tube with external choke. I rechambered it to .357 Maximum myself. It now shoots .38 or .357 wonderfully too (unlike a factory TC Maximum barrel).
The .350 GNR would be best for the Encore to get the most out of it. The .355 GNR would be much more efficient and well suited to the Contender chassis. NO headspace issues and a nice ample rim.