MS, there is no reason not to get a .35 Remington barrel for your Encore. It is a proven cartridge and with the single shot action you can use a wider range of bullets, if you so wish. I have used my 14" .35 Remington Contender to take game up to moose, although that was a bit of a stretch. One of the few issues with the .35 is excess headspace with some barrels - T/C and Marlin. Getting a quality custom barrel with a good chamber should eliminate that issue and deliver even better accuracy.
Some will say that there is the potential for safely loading the .35 to higher pressures in the Encore, but without published data I would not recommend it. Afterall, standard load data has worked for over 100 years...
.
