I built the Dominator 500 per the instructions and flew it with a 46FX and Jett 50. I had no issues with the quality of the kit and it flew as well as any Q-500 I have owned. Mine was set up for sport flying with the longer ailerons and I would make them even longer if I did it again. I am surprised the daven did recommend a 10 x 7 since you are using a 46 AX. I liked the 9" prop with the higher rpm engines. Glass the firewall and wing center section and it should hold up fine.
Q-500 planes with a tail skid do not taxi well. A tail wheel may help with taxi but takeoffs can be tricky if you do not have a helper release at full throttle.
When you get ready for a Delta I know where you can get one.
