Hi Bruce,
The jittering is normal. Sometimes the Spektrum Comparator product SPMCP will solve it, other times not. Letting the plane sit a little isn't a problem, since you'll often have lots of time with the model on the ground before flight anyway. I have a 6V system in my H9 P-51 Marie and it buzzes a little. It doesn't matter.
With that setup I would go with the 12ch. Yes, it's the cleanest, and it has the fewest connections. (A Y connector adds 12 connections to a system. A servo is worth 3). I would have as many straight runs from the servo to the receiver as possible, and eliminate all the Y's completely if I could. You should be making your own servo extensions (or have somebody do it for you) on a plane like that. I would, anyway.
Andy