RE: help needed once again...
I wouldn't sweat the fuse side strength. It's doubled. There is a phenolic tube CA'd to both sides just behind the location of the "J" hooks or 1/4 x 20 bolt holes. There is a servo tray that is glued to the back of the phenolic tube, both sides and the former at the rear of the wing bay. There is a former just ahead of the "J" hook location.
Just make sure that the nylon bolts can't vibrate loose.
Did you add blind nuts to the insides of the root ribs? Or maybe a threaded hardwood block?
BTW- the stock approach is simply #64 rubber with 3 loops. How much "pull" does that rubber band exert anyhow?