You could probably substitute the 190 proof grain alcohol for the ether - they perform similar functions. Try it and see. The other thing to think about with this process is that you will have to devote a camera to it, and you'll have to not be too invested in that camera's long-term survival. The wet collodion plus silver nitrate will corrode the metal of the camera over time, even if you are careful and wipe down the film transport area between each exposure. You'll also have to modify the film pressure plate so that it does not break the glass when you close the door. You won't be able to use one of your Leicas for this, as they don't have a back door to load the plate through.