Yes; and yes.

One partial solution, if one wishes not to glue them in, is to glue in a piece of dowel within the tube where the screws go, so they are biting into much more than thin aluminum.

This does not solve the problem of the spar tube loosening in its fuse receptacle. I have only flown mine for six flights, and already the wing tube is getting looser in its fit. You cannot convince me that the same thing isn't happening back in the tail. But my stabs are firmly glued in placed, so I don't worry about it.

And while my building skills may not be up to par with some, there's really only one way to put this thing together... it either fits, or it doesn't...