Also, just in case anyone's looking for a good dealer of vintage ones, check out Jake at Antebellum Instruments: http://antebelluminstruments.blogspot.com
He does all that complicated setup work for you. He's in Vermont.
Unless you know what you're doing..it may cost even more than a luthier to do it...as you now learned...it's a costly lesson...maybe next time do your homework and check on
You tube video how it should be done....or ask here..
I gave my two vintage banjo ukes away. I prefer modern ones - I have a Goldtone baritone which is nice (I would have made it a 10" pot if I were the manufacturer, but wotthehell).
Once the vellum cures, you can take it off and readjust and rotate the head as needed. It'll still hold its shape. I've put new calfskin hides on 3 vintage banjo uke now. I usually take the banjo fully apart, so I'm just working with the pot. That way I can get all around it and get a good even pull on the excess.
Ha-ha, real tinker-toys, aren't they! Are you happy with it now? My first banjo-uke (I only have vintage and would not buy new....) was a real beauty but needed lots of fiddling to get it playable. (Slingerland bird's eye maple...)