On my HotSpot, I plan use dual servos (JR 8231) for each elevon. Should I split each elevon like the instructions show or have the servos actuating the same flying surface? With regards to servo failure, I've only experienced a few in my 26 yrs of flying RC, two just died, the other skewed to the limit (broken pos+ wire). I don't foresee a wire breaking with the 8231's but the newer (digital) servos are more apt to slow down or just die if they fail which in this case would favor two servos sharing a common elevon. Whaddya think?

Most guys run single 8411's on single elevons with no problems.

If you are looking for redundancy then the best choice would be twin servos on a single surface, that way if one servo fails chances are you can still move the surface and maintain control.

With split elevons you still have a single servo on each control surface. If a servo fails and locks up you still have a deflected surface and will have control problems, just like a single surface/servo situation.

I am guessing you have the Graupner kit which I believe uses the split elevons. I have the Jet Team Liebetrau model which uses a single elevon.