Hi
For the last 10 years Ive been using the guillotine style paper cutter to cut down sheet film (Xray) of various sizes. I find it easiest to have two cutters, one with a stop taped to one dimension (say 8" of the 8x10 size) and the other to the 10" dimension. That way you can cut all your film to the first dimension, then move the stack of film to the next paper cutter and cut the second dimension. I do this because 8x10 feels just about square in the dark. 4x5 is simmilar but 5x7 is less of a problem.
Ive tried a number of safelights and despite what you may read, most xray film will fog with a red light to some degree. Having the stops taped down to the paper cutter really helps to index the film correctly and elliminate the need for a red light.
Xray film has very thin emulsion on both sides (Agfa Mamo-ray doesnt but its horrible to work with) so you need to have that paper cutter both clean and smooth before use. The stuff will just abou scratch by looking at it, especially when wet, so once the film is on the paper cutter DONT slide it around. The same goes for developing, I use glass tanks where it can be hung vertically, and its about the only way Ive found to avoid scratches. Just recently however I heard that ziplock bags can be used to develop in, if your carefull, as they are smooth on the inside....I have not tried this myself though.
Hope this helps,