heh, cool! String it up with the DGBE from a guitar set, that might help the volume a little.

The height of the saddle does have some effect on volume, but it's probably not a very responsive instrument to start with.

Harmonys do have some collector value, not much, but enough so that you want to keep it as authentic as possible. I've restored a few junkers and sold them (electrics), three to four hundred for a restored semi-hollow electric is pretty much top dollar. Dunno what a tenor in good shape would bring, probably quite a bit less.