Move them now getting as much root and soil mass as you can and have the receiver hole dug first. Then plant as usual watering well. If it's already time for you to prune, you could do that, if not wait for the forsythia to bloom. I plant mine with some alfalfa hay to help with root establishment, but if you get a lot of root/soil mass don't worry about it. Also, wait until you see new growth before lightly fertilizing. I've done this many times even with monster New Dawns and they didn't miss a bit. They will thank you for the sun.
