Just thought I'd let everyone know... I've been doing this since I found this guide a few months ago and I haven't had any villagers move since then. It's extremely helpful and I would recommend to everyone!
Good guide, TYVM! Will start using now, as I am TT'ing to get a villager moved out in my one town, while making sure no one I don't want to move leaves in the other (both on the same DS).