Run a front brake... you'll be glad you did.. way more convenient coming up to a stop using a front brake and not having to worry about how your pedals are oriented .. in practice, I use the coaster brake to scrub off speed and then apply front brake as needed..

In regards to the belt tension, with the C-drive 8mm pitch system, you don't need to run a lot of tension, on mine, very relaxed tension and proper adjustment of the belt snubber is all you need... your hub bearings will thank you and the bike will have less pedal drag.. nice thing about running 8mm pitch belts, there is a much wider variety of belts and cogs to fine tune your gear inch number.. a couple of my coaster rides..