How to string and tune an American (non-British) six-string fretless?

[razyn]

This is off the wall, but last week we were playing with some old-timey sorts and for one or two numbers they wanted my wife to beat rhythm on a drum head without any jangles (i.e. more of a bodhran sound, and not a tambourine).  I've had a few unrestored "project" banjos lying around for a decade or three, and thought if I could put a head on one of those pots it could be a drum for the gig last Thursday, and then move on to being the banjo it was built to be.  So I decided on the one for which I had enough brackets to complete the job, and that turned out to be a six-string fretless.  The back of the badly torn head has this penciled inscription:

Belong to

W.H. Gibbs

Fletcher, N.C.

Feb, 3, 1912

A Son of W.H. Gibbs

now own on July 1, 1944

W.R. Gibbs

The neck is black walnut, wide and thick, and would be a pretty normal "minstrel" type if not for the extra hole in the peghead.  It's never had screws in it to hold mechanical tuners, so I guess the missing pegs were all friction pegs of the violin type. Tailpiece and bridge were also missing.

The 16 brass bracket shoes are the shield type, with vertical stripes and three stars across the top.  I can put up some pix if anybody wants to see.  Mainly I'm curious about the pitches for the five long strings.  Bernunzio had a similarly drilled one that was just restored to play as a 5-string, by ignoring the extra hole.  The metal nut of this one has been notched nine times, in order to accommodate either five or four strings, evenly spaced.  The notches look too thin to have been intended for gut strings, or even very heavily wound ones.

[Trapdoor2]

S.S. Stewart, in his 1896 catalog, listed his 6-string banjo (five long strings, one short) with the "extra" bass string tuned to F. Thus: gFCGBD. Some people tune gBDGBD (my Gold Tone OT-6 is currently gBDGBD). Of course, for something earlier, one would take the whole tuning scheme down several steps.

Thin string notches may indicate later use of wire strings or silk strings (which were very thin). I have a vintage set of early 20th C. (I think) silks that are amazingly thin (and fragile).