Well here is Ilfords publication on processing, and its pretty decent, although I don't insert the paper the way they do, and their way seems weird. Ilford mural printing guide But it will give you an idea. You can buy plastic troughs for hanging wallpaper and use them or if he's going to be doing this a lot, I'd suggest making a 5 or 6 bath dedicated system out of 3/8" or thicker plexiglass, with drains that have a screw tube into them for easy drainage. I've got plans for that if he's interested. Its pretty basic but after doing mural printing for a while, you figure out easy ways to do things, processing wise.

As for drying, the easiest way, although you do need some space, is taping them on particle board that has that smooth, white surface on it. You squeegie the excess water off, them use kraft tape, the kind thats brown and has fiber web in it. It has a wet activated glue on 1 side. You attach this tape to the print and board. This will make the print dry flat, and therefore you don't need any type of press to flatten out the dry print. If space allows, you can then either lay these flat, and stack them on top of each other with spacers inbetween, or stand them verticle.

I've done hundreds of murals and didn't have a press. This made the most sense to me, and reduced prost production of flattening the prints.

I am currently looking for a horizontal enlarger and thats why I was curious. Used one are usually far away, thus increasing the price thru shipping. Plus, the sellers still are trying to charge to much for them.

Hope this helps.