I'll base a response on what I saw in the email. 1. It doesn't have to be out on the underside of the wing very far, so the wiring run would be minimal.

2. I doubt the engine exhaust will have much effect as far back on the fuselage as you're proposing.

3. I don't see enough room on the fuselage under the wing to mount it that would keep it out of the sun. That would also place the back side of the sensor inside the cabin, which can affect the readings.

If you're absolutely dead set on not mounting it on the underside of the wing, your rear fuselage idea is probably your best bet. I'd put it as far back as possible, just to be safe. You might want to post this question on the Dynon forums (https://forum.flydynon.com). Someone over there may have already done something like this.

Fred, I got an email today that says you sent a message to everyone in the group about your OAT sensor, but when I come here I see no such message. Did you send one, or is the system playing tricks on me?

I am sorry ,  his email address was wrong on several roster postings. I am EAA Chapter 175 treasurer and seems its been wrong for awhile. Try this one 

rleblan@verizon.net

Hi Fred, copy his email and compose a new msg and try to reach him that way. Some reason when you reply with Zenith message it does not like to used outside email address for some reason. I seen his 750 cruzer and paint job looks good with a roller.

Hi Fred,

could I please have a chat regarding your autopilot build…. 
bfreeppg at gee letter blah blah ( code ) . 
Regards

• Tony Renshaw