Hi Labron,
There are two ways to go. Since you say you are using a 12-channel receiver I suppose you have a 12-channel system. In this case you could use the PowerExpander Competition 12 and do all your servo matching in the transmitter. I have heard that one of features on the JR 12-channel that helps do servo matching did not work on some of the first units so you may want to check with Horizon about your particular transmitter. The other way to go would be a PowerExpander Eq10 and you would do the servo matching using the Eq10. Please let me know if you have any other questions.