i scratched out a fuse like that and made as to match LT 40 specs and put a spadet wing on it to train my last student on....worked fine still flies! and its easy for any one to fix. i used pine door stop trim for the rails and 1/4'' balsa for the box with big tri stock balsa in the corners.
Don't glue the box to the rails until all is assembled and you can balance it like any spad.