Tail angle of 37 to 40 degress from verticle should be about right. I would post this question in the slope forum at RCGROUPS.com for a much broader audience to answer this question. Some of the most famous names in RC flying hang out there and are eager to help. Rcuniverse is no where near as active as RCGROUPS and I'm sure you'll have many more engineering related questions as your project progresses. Also, check out what the angle of the V-tail on the Dynflite Talon is. That should give you a very good start as the Talon flies rather well with it's V-tail arrangement. Hope this helps out. Jim