What "channels" are you talking about? Telemetry devices don't have any channels. Binding doesn't make any difference - if it's already bound, power cycling the rx is the way to add new XBUS devices but doesn't do anything for the internal ones (V, RPM, Flight Log, temperature).
Is this the sensor you used? SPMA9569 -
http://www.horizonhobby.com/products...acket-SPMA9569
I think your solution deserves a thread of its own with photographs.
You are correct, RPM needs to see continuous data for a while so it can filter properly.
Andy