Try this calculator

http://brantuas.com/ezcalc/dma1.asp

I am a avid fan of the the EDF and will probably never have another propeller driven model. But $ for $, amp for amp, a prop beats an EDF every time.

For your 6 foot A10, a propeller pushed version will be much less expensive, especially if you use props larger in diameter than the nacelle. You could mount them pusher or tractor