I read your page on your website about e-bay fakes and thank you for taking the time to produce the page.
I produce ambrotypes at Civil War Renactments and sometimes sell ambrotype copies of popular Civil War images on e-bay--Robert E. Lee,Hanging of Lincolns Assasins,Grant...
Here are a few ways to tell a modern ambro/tin from a vintage one;
I can tell you that most Reneactment images are usually of the 1/4 plate or larger size so I would be leery of any soldier image in that size be it a tin or ambro.
Most modern wet plate Photograpers etch their initials and sometimes the date in the corner of the glass or tinplate.
Check all images with a loupe for a fine dot pattern(I only copy images with a dot pattern for sell on e-bay) a sure sign of modern.
Smell the plate--I can still smell the lavander oil varnish on plates I made two years ago.
Check the "tintype" with a magnet- it may not stick as some modern wet platers use alumminum plates!
I have seen so many fakes sell for high prices on e-bay that it makes me sick to think about it(Lincoln seems to everyones favorite followed by any Indian).
You may want to check out the seller nugatoryman for a good laugh.
Many of his items look very similar to the items you show on your website for spOOler. Every week there are fakes for sale and they are definetly on the increase.
Hope this info helps some .
Tim Parson-------AMBRO----on e-bay
Parson's Photographic Studio
P.S. I have enclosed a scan of an original ambrotype taken by me in Feb. Of this year