Especially in this case.

Your idea about installing the bolts from the inside would work, although I find trying to tighten small nuts kind of a pain.

What surprises me is that you have such tight clearances. With a 4*120, you're flying with what? 3.5 or 4" wheels? So I'd think your LG setup would be an aluminum strut with a bolt-through 3/16" axle? If that the case, the normal sort of lineup from inside to out would be strut, wheel pant side, wheel collar, wheel, another collar, and the outside wheel pant side. So you should have 1/4" to 3/8" of clearance between the side of the wheel pant and the wheel hub.

I'd try something like this: epoxy as thick a wooden plate as possible, probably 3/16" or 1/4", to the inside of the wheel pant. Then drill the pilot holes as mentioned before. Instead of using wood screws, put in a #4 or #6 blind nut on the inside of the plate. Then drillout the holes in the strut to take a #4 or #6 socket head cap screw, trim the screws to the length you need, and then you can bolt the wheel pants to the struts. This should give you more strength in the mount. If you're worried about rough landing destroying the wheel pant, use a nylon bolt on one side of the strut so it can shear off and let the wheel pant rotate.

Wish I could draw this, but you'll have to take the 1000 words