Hello Jim,
I have that same Gundlach lens. Does it alter/improve the vignetting at all by removing the lens hood? I don't have a flange for mine either, so I have not tested it. Best research I could do indicated that Gundlach fits a Simplex 35mm motion picture projector, probably from the early 1910s or so.
To the OP, doing a search for
Petzval will yield some results, but rarely any bargains. Another search for
Magic Lantern, which is an early type of projector for glass plates, might get you a few other lenses, though it will take some alteration to make those work. The biggest problem can often be the lack of a mounting flange. If you want to look for more specific lenses, you can try the following terms:
Ross, Holmes, Petzval, Derogy, Suter, Dallmeyer, Hermagis, Auzoux, and Busch. Those are not the only Petzval, old, or rare lens makers, but a search for those can yield some interesting results.
A 1/4 plate lens would vignette, except at closer (head shot) distances. My Homes, Booth & Haydens works fine for head shots, though would slightly vignette at full body distance. However, I like the focus fall off away from the main in focus area, like in this example:
http://gordonmoat.com/life_20.html
Biggest problem I have using this is the lack of a shutter, though I now have a Packard shutter that I will adapt to my Shen-Hao. Second biggest problem is shooting wide open at close distance, because people tend to move just slightly. It might be easier to have someone sitting, instead of standing. Anyway, Jim Galli is much more of an expert on this than I am; I only got my H, B & H through a bit of odd luck: it was included in a large pile of camera gear, and I happened to clean it and try it out.
Ciao!
Gordon Moat Photography