I have been using Entropy for years and I swear by it. Hands down the best archive app for OS X (yes, it fully supports creating RAR files). It's kinda on the expensive side, I bought it when it was on sale for under 10 bucks but I think it's worth every penny: https://itunes.apple.com/us/app/entropy/id437151949?mt=12
After you can use automator or action folder to perform the task with drag n drop. Cost at the end 0$. Require a little effort, but in the end can give you full control on the way you make your ear files and automatization of it.