[Dale M.]

For ultimate safety all tanks should be outside. Period. But in some commercial/industrial setting its is legal to have small tanks inside.... Check local fire codes.....

A manifold system is probably what you need and it can be made up from black iron pipe and using readily available valves and fittings usually sourced from welding supply sources...

Western Enterprises comes to mind..... The are major manufacturer of brass fitting for welding industry and their products are retailed in many welding supply and i-net sources...

http://westernenterprises.com/enterprises/

Teflon tape is typically used on tapered (NPT- National Pipe Thread) threads and NOT used on any straight cut thread the depend on a metal to metal contact (propane tank connections) for sealing..

Though yellow Teflon tape is "gas rated" its not really a absolute, plain white Teflon tape is same chemical compound as yellow and is quite acceptable... Also its not actually used as a"sealer" its a actual a thread lubricant and allows one to apply more torque to fittings and get a better seal on thread to thread contact... IF you have poor performance or problems applying tape, plain old "pipe dope" is acceptable....

Dale