i used stronger wood for my joiner. 1/4 ply aircraft grade. Look at any instruction sheet to a kit built plane and you always glass the center. it does make a huge difference. I fly mine on the saito 80 after a full power t/o i throttle back to half power and that is plenty for loops and rolls. with a long tapered high aspect ratio wing which is thin, you must be very careful on loads applied. I have seen guys who just tape the center together with no glue! insane
Tube spars are much stronger therfore are designed to remove the wings. Again how many overpower the aircraft and do aerobatics, it is a civil private aircraft. On the box is does mention aerobatics which is silly the real aircraft is not designed for it