Ralph,
Farm boy or not from what I have gathered, you're an excellent, experienced pilot. My point in determining a top or bottom antenna is the strength of the signal. The SL30-40 seems like over-kill in a low-and-slow aircraft...when something like the MGL V10 is half the weight in a 6 watt com.
So, I am asking, would that be a good direction to go with a top mount?
Ran