If you want a tight set up with the 13/3k, turn your tank facing the other way. The "butt" of the tank facing towards the barrel. I used to run a Phantom the same way with a 4oz Co2 tank. It was very tight, but it still lets you run a reg to drop that pressure down to something usable with your tank.
Current Collection: Bob Long MVP - Bob Long Vice - Bob Long Defiant - Empire Axe - AM-P Illusion - Tippmann 68 Carbine - Tippmann SL 68 II - ICD Promaster