I'm looking at photo of an old banjo, labeled a plectrum. It has 20 frets from the nut to the tension hoop. Then a fingerboard extension over the head with another 3 to 4 frets (last one cut off by curved end of fingerboard). It's a nice banjo I might want to convert to 5 string, but only if the neck is truly plectrum length to the tension hoop. Or is some sort of lengthened tenor?
Thoughts?