You have to be very careful filing them out, all your mistakes are highly magnified! I have one for my V35, and mainly use it for bigger enlargements as it is double glassed, making the negs very flat. I personally use a 1C with the oversize carrier for a lot of the smaller stuff, the line is much finer on that carrier, which I prefer.
The auction site being referrred to would be Ebay, give it a try.