The fitting that goes through the rectangular clamp and mates to the scuba tank is threaded into the bleeder valve. Not positive, but I'd bet money that it's 1/4" NPT. Unscrew the scuba fitting and screw in the cylinder nipple and I should be good to go. I should be able to get the nut and nipple from my cylinder supplier. The reality is, none of this should see over 3K PSI, unless I screw up, and in that case, the burst disk on the Talon tank should save my butt. If you never hear from me again, you'll know I was wrong :-)! Hopefully, I'll be able to post results one way or the other tomorrow, assuming I can get a cylinder. Later.
Dave