Welcome to the party, Monte. Glad to see a brother here.
I can't help you with the deck angle, but I'm curious why you chose the RC Allen vs. the Garmin or UAvionix offerrings, which both cost less?
I don't have a dog in this hunt, I'd just really like to know, as I may be in the market soon myself!
Someone will come along here soon and answer your angle question.