How can I route *some* traffic over an SSH SOCKS proxy on OS X?
Quoting from the author's website:
Transparent proxy server that works as a poor man's VPN. Forwards over ssh. Doesn't require admin. Works with Linux and MacOS.
https://github.com/sshuttle/sshuttle
I'm not yet sure how to make only certain applications traverse the vpn yet besides that it fits your needs just right. You can specify the route in the start parameter so only certain destinations are tunneled.
You don't need to touch your application in any way so disable any socks setting that you might have.