Will,
Yes, I could probably make two L brackets but it will be tight. I solved it in another way, as my motor mount is glued to the airframe I simply did a small support between the lower/most inward part of the motor plate and the bottom of the engine cut out. That cured the last wiggle.
Thanks for the photos, I cant see the 1/16 music wire on the inside part of your Cardinal, is it hidden under the covering?
What did you use to glue your wing? Epoxy, CA, White glue, etc...?
/Andreas