You didn't indicate the Zone you are living in. Here in UT we are back into the 100 degree temps- not the time to transplant. If you wait until your weather starts to cool down in late summer, you should get good results. There will be plenty of time for the root stock to get settled in before winter. Be sure to leave as many of the leaves on as possible to that the sun can help build up the energy storage needed during the winter. As the leaves die, take them away to keep the area clean. That also helps to keep the snails/slugs down & the earwigs away.
Haven't tried it yet, but read a short piece by Jerry Baker, "America's Master Gardener" about slugs/snails. Too keep them out of the rhubarb, take some copper tubing (it has to be polished so no green is on it) & lay it in the path they take to get to the rhubarb. Seems that the slim they make has a chemical in it that reacts with the copper, producing an electric current. That kills the critters right then.
