Si
The Gaskets under the Valves (see pic above) are almost indentical to those used on the Zeagle Bladders under the OPV Valves. I have a bladder cover or two spare that I can pull the gaskets off. I Will bring them down to Sydney next weekend and we will see if they are the right dia, maybe we can use your Dremal to cut the hole
. Then you just have to glue them down onto the CL and screw down the Manual Add valve.
Another idea might be to order some of those Double gaskets from SMI that I got in for my exsisting ADV.
Cheers
Chriso