It's probably going to be easier to just "suck it up and rubber band it". It's not impossible change a rubber band wing to a bolt down wing, but it does require quite a bit of structural changes to the internals of the wing. It's not as simple as putting a couple of nylon screws through the wing and flying. You have to ensure that the front dowel of the wing is tied into the main spar of the wing to ensure that the loads are transferred evenly. You also have to build up the wing area where the bolts will go so that it doesn't crush the wing.

Like I said, it can be done but it can be a bit of work.

Ken