Tom
I suggest you take a look at the following link.... http://groups.yahoo.com/group/CitabriaPilots/.
We had a discussion on this between Nov 20-30 2004.
Basically it looks like for the 7eca and 7GCBC, the attachments are clamp on type, no welding required and you are looking at a 2 hours job. Not too expensive either. Now I am not sure for the scout though.
Bruno