I have made a 'hopper' - a u shaped support that has a dowel though it to hold the roll of paper. My rolls to date have never been larger than 12". Bob Carnie has put posts out on how he has cut down large rolls by wheeling a table saw into one of his large darkrooms.

I use a guillotine cutter, with no guard in place to risk scratching the surface of the paper. Yes, cloth gloves. Length guide was a piece of scrap 4 ply matt board taped to the base board.

Have a plan in place on how to re seal the bag once you opnened it, and make sure all tools needed to do this are carefully positioned before the lights go out, and the bag is openned.

Even in a non carpetted space, vaccuum the day before. If you have a humidifier, use it to keep the static down as you drag the RC paper back along the cutting platten.

Oh, and blow your nose and go to the bathroom before you begin. It can be a long session ,a nd you don't want to have to leave part wary though.