Certified GKH Gardening Expert
In terms of the size and repotting, it sounds like your plants need to be divided. Take the plant out of the pot and with a sharp, clean, large knife, cut the rootball apart into sections you find manageable and then repot them. Just make sure that a stem above has some roots below to sustain it. I know it sounds a bit brutal, but really the plants recover quickly.
First, good for you. An exploding jade plant - how wonderful. Repotting is vastly over rated, in my opinion. You only need to repot if your plant is so big it's falling over, or so full of roots it can't retain water. So if you don't have either of those conditions, let it be. If you do decide to repot, water a few days prior, select your new pot - no more than 2" diameter increase - and using some potting mix for cacti and succulents, put some in the bottom of the new pot, carefully remove the plant from the old pot, put into the new one, and fill around the sides with soil, water in the new soil, and continue as you have been. Don't be afraid of repotting - bonsai growers routinely cut off much of the root growth when they repot. The only thing you need to be careful of is not to break the main root where it joins the stem. Of course, if your jade has multiple stems and you want to make a bunch of plants out of it, cutting apart is always an option.