stick a piece of steel or aluminium at the back where it joins or else the glued surface won't hold. (not to be negative but been that soldier and it ain't fun)
Ya...I have to go along with bone-ified...that probably won't work. I'd re-think that joint. It would be a shame to put alot of work into the rest of the instrument, just to have that head fail when you tune it up the first time! Not trying to rain on your picnic here just trying to help you do it right. Don't take too many shortcuts or it will suffer structurally and acousticlly!
Comments
Check out A Guide to Advanced Cigar Box Guitar Making by Josh Gayou, contains an excellent article on making a scarf joint . (-:
http://www.cigarboxnation.com/page/free-plans