RE: EDF jet motors
Picking a motor needs to start with the fan you intend to use. Once you know the fan and figure out the model you want to run it in research the fan unit on forums and find the power required to give you at least 75% thrust to weight. You can go a little less for planes with lower wing loadings and need to go higher for more heavily loaded ones. (think A-10 vs. F-104)
The trickiest thing about EDFs is you can't adjust just select a different pitch or diameter to match your requirements, you have to match your power system to the fan in increments of cell voltage. for instance; say you have a 64mm fan with a 4000kv motor that pulls 25 amps on 3S and 40 amps on 4s, if the plane needs 300 watts to fly and the motor can only handle 30 amps you can't use that motor on this setup. You will need to either get a motor with the same Kv and a higher maximum amp draw (heavier) or a higher Kv for use on 3s or a lower kv on 4s.
A word about motor selection; in general heavier handles more power (wattage); outrunners have better cooling so handle more watts per unit weight; higher Kv motors handle higher amps but higher voltage is more efficient.
Test your fan setup on the ground to be sure what it will do. flying by at 100+ mph is a bad time to find out your setup is cooking your ESC. Test your setup on the ground by using a wattmeter and an IR temp meter or temp probe. run up the motor and check your readings to make sure your within reasonable parameters.