The saga continues. Even though I just posted this information in another thread, I'll duplicate it here for the record.
So it seems my American Optical camera was made between 1890 and 1899, possibly originally a wetplate camera, though the back is stamped "American Optical." It was later folded into Kodak, but ANSI standard for filmholders dates to 1918, so it is possible that the back is nonstandard, though I purchased the camera from someone who used it with holders that he says were standard.
So now I need to figure out whether the back is nonstandard, or the holders are out of spec. I've emailed the photographer I bought the camera from to see if he would be amenable to doing some tests, if he has other holders and another 11x14" camera, which I believe he does (along with the beautiful Lotus 20x24 in his studio!.