I think the recommended method is known as "sizing" which is done by using a diluted mix of wallpaper paste and coating the walls with that, so the new plaster soaks it up. It is left for awhile to soak in and then you can paper as normal. I have nothing against using PVA but it is said to have a reaction when it becoming moist agian that it fails and won't bond!
Try your post on the decorating forum you may find better knowledge there.
Plaster can take six to eight weeks to total dry out, but I've worked on many a building site and the decorators have never waited that long!
Best of Luck, sorry can't be anymore help but i'm sure i've pointed you in right direction.
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