I would go .686 and punch shallow to medium wedgits (or wedgit like) setup.
As for your tube length for the springfeed, I've been a fan of the 12-15ish range. 20 balls stacked side by side, the springfeed, and ramp is a lot of real estate. Double that by 2 and... well have fun reloading that sucker.
Originally Posted by russc
Senghing, you are the happiest paintballer ever.