DIY pressurized CO2 system and Hagen valve

["Davorin Palijan" <davorin.palijan at os_tel.hr>]

I've got a CO2 tank and Micro Matic regulator for free!
I just hope they perform OK, because they are used.
Anybody knows what is expected life of these things?
Regulator is two gauge, and it shows 56-57 bar inside
the tank and I set it to 0.5 bar on the output.
(1 bar = 14.5 psi)
My question is about needle valve (or lack of n.v.).
I was unable to find proper needle valve around here,
and closest I got is Hagen small "needle" valve for
reducing flow of aquarium air pumps. It is very small
and made from transparent plastic. It does have "needle
valve like" type of construction and with little bit of
teflon tape around needle thread it worked for reducing
the pressure to 1 bubble every few seconds (measured
in the bucket). First few days the pressure droped from
1 b/3sec to 1 b/5sec, but now it seems stable.
Should I try to use it for longer period of time or try
to find something made from steel?

Thank you!

Davorin from Croatia

P.S. Thanks to Chuck and all of the other people for reporting 
on AGA conference - it means a lot to us who were not 
able to participate (it's just so darn far away!).