So your hobby shop owner gets his mind blown by a 4 channel glow trainer plane. That's just sad. I'd seriously consider walking in and explaining that some experienced pilots showed you what was wrong with the way your plane was set up and asking him to either do it over correctly for free or refunding your money. If he offers you store credit, take it and spend it on parts and fuel. Hopefully the owner can run a cash register without screwing that up too bad.

To fix the rudder/nose wheel issue, switch the control horn to the other side of the rudder and run your pushrod out to that side. Problem solved. That may also require moving your elevator control horn too.