Ooooh moving coops. This is a big challenge with opinionated, very highly set-in-their-ways guineas.
Honest, at that age, I went out every single night after they were roosting and chased them to the place I wanted them. To do this effectively, the coop where you want them to roost must be lit, because they will only go if they can see where they are going. If you turn on the light before dark, they may start roosting there more quickly. It took me several months to get them trained to consistently go where I wanted them. It wasn't a big hassle to move them, I just stood behind them so that as they flew away from me they were flying toward the roost where I wanted them, and I waved my hands and scared them off their roost, they headed toward the light and in they went. It was not hard, but definitely a nuisance because it took so long for them to learn.
Another idea is to lock them in the new coop for 2 weeks. I know that isn't what you want to do since you just got them free-ranging, but its another idea.
Moving their food and water into the new coop will encourage them to go in there during the daytime. It will not break their habit of roosting in the old coop, but will help make it much easier to get them in the new coop after dark.
