Hmm. That is interesting Brian. I suppose I won't figure that problem out until several flights in when I test the auto pilot.
Regarding the GTX45R, I haven't done the research but my GTX345 has a WAAS GPS and I thought the R version was the same radio without the control panel.
I could be wrong since the GTX345 is certified and the 45R I notice is designed for the experimental/LSA market. I would certainly get the answer before I spent the $.