Hi Digger,
I'd be a bit careful, it's possible the 22mm is the fat bit in the middle. The outlets are probably a lot smaller. It also seems quite narrow, OK for an O2 RB but I'd maybe think about going bigger before you spend anymore on mods.
On most RBs there are one way valves either side of the DSV and that's it. The only real reason to have them anywhere else is where they are doing a specific function like on the RB80.
Try
www.vintagescubasupplies.com for decent one way valves. Many others don't stand up too well to diving use.
Cheers,
Stuart