I have to admit that I didn't build a arrow with central elevator, so I duno how it fly.

What I know is that the two elevon setup work, great, that it allow you to save some weight, the roll rate is very very fast.

The only dark side that i can see to this kind of flight control setup is that if one of your flight controls servo fail during flight the airplane is definitly dead.

it's possible to control a plane with one aileron working and elevator or make a controled crash with a inoperative elevator servo, but it's impossible to fly a delta with only one elevon operating.

so install good servos in case of elevon setup