With all the mods you are making you'll have to put the word experimental in front of Kangaroo. The rudder idea sound very cool. Probably be able to do flat turns with them. Aileron stock should be fine. I checked my vertical fins and they seem stiff enough. Only question I have is where are you going to put the servos? That wing must be getting crowded. I have been looking for other threads or possibly a U Tube video on this ARF but am unable to find anything. Have you seen anything? I've see jet versions of the Kangaroo fly here in Pennsylvania but never a pusher version. Hope to have my Mustang done in a few weeks so I can start the Kangaroo. The weather has not been good for flying here in the Northeast. Good luck!