cas i did the same mod on the joiner for my Midwest 300 S but went the other way i got rid of the aircraft ply and went with light ply with carbon fibre between it held up for about 6 years till the guy i sold had his radio lock up and the plane went in . the way you did the joiner is the way to do it good idea on your part

as far as the landing gear i think a few other guys said the way the gear was designed it was trying to pry the wing apart . looking at the picture there absolutely right Mickey Mouse desigen

JIM