I need a 6x9 negative carrier. I have a glassed 9x12, shouldn't that feasibly work pretty good? Or do I really need one dedicated? There is one in classifieds now, that is 2.25"x3.25" roll film, that should be the right one, or is that for some obsolete roll film size? When I measure the negative gate in my back the carrier seems a wee bit short.
The important thing is the guide pin spacing. Some older Omega carriers are made for narrower 2 x 3 cut films and wont accept 120/220 films. Its not unusual for eBay sellers to mislabel old cut film carriers as 6x9cm if they are unaware of this
In my opinion it's better to use the glass 9x12 with a mask, because normally a 6x9 glassless carrier cuts off too much of the negative area unless you file it out a lot.
I have filed out Omega D5 carriers -- a pleasant way to spend the time while watching the rain fall. I have also taken D5 35mm carriers, then cut and filed them so that they would print two or three 35mm negs at one go.
I have something that approaches 6x9 for my Omega D4, but like the previous poster with the Durst machine, it's really closer to 6x8. That doesn't bother me so much since the only 6x9 negatives I have are either very old and come from what I'd call crappy cameras, or come from a very old 6x9 Kodak folder with a crappy lens. I'm not shy about cropping so I compose a little loosely, and don't worry about a stinking little 1/2cm. off the top and bottom. The image quality at at the edges is so bad that it's no great loss. I'd feel differently if I had a high quality 6x9 camera, but I don't so I don't worry about it.