Talon SS micro metering valve

I am in the process of tuning my original model R0001 Talon SS that has languished in its case for a couple years. I want to go through the O rings and make sure the gun is ready to go back into service. I only do 11 meter target shooting so I do not really need high power shots. A few years ago I bought the CO2 adapter and a paint ball HPA 3000 psi tank with a regulator so I could get hundreds of shots per fill. It worked great but the tank is bulky (48CI) with no butt plate plus the added length of the adapter. I miss using the Talon tank with its handy adjustable Morgan butt plate. From the reading here it seems like the micro metering tank might be more appropriate for my needs. However, it is my understanding that one must purchase the complete tank set up ($200) rather than purchase only the valve.

I find it strange not to find O ring service pack kits for these rifles anywhere or at least a sticky with the appropriate size numbers for these small parts.

The air gun world, as well as this forum, has changed a great deal since 2008 when I bought my Talon but of all the air guns I own it is still my favorite. Suggestions and solutions are welcome.