Alan:

Regarding the remote frequency selection issue you asked about:

<<<
4. The Garmin SL30 will allow for the selection of frequencies
 directly from the Chelton.  The SL40 will not.
 
Is that a true statement?  I guess I've never asked, but I thought the
Cheltons would control either the SL30 or the SL40?

I guess I'll go ask the source :)

My Chelton (Pro) selects frequencies on my SL 40.  Carl Lewis
Legacy N14CL