I have been wanting this exact setup for a while now. I am looking at using an adjustable output reg like a maxflo or an Armageddon, on a 68ci slave cyclinder attached to the SCUBA tank (like above). then run a long remote line to the marker for testing/tuning. the idea would be that I could simulate different output pressure tanks. I work on bob longs (LP sometimes SLP), cockers (usually 550-850) and Automags (850 and up) and I would like one setup to run them all correctly.