I use mine constantly and find it indispensable. I processed my 4x5 in a tray until I picked up the Jobo set and have not gone back since. In the beginning I loaded without the base and found it easier to load the outside slots on each side rather than try to use the 3rd, inner slot as well. That meant I could only develop 4 sheets at a time but that seemed to work ok. I picked up a loading base about a year ago and it is now delightfully simple to load the reel and develop the film. I now have two reels and can shoot two loads in my Grafmatic film holders in the morning, load them onto the reels and develop in the afternoon.
BTW, while theoretically possible to do it in a changing bag, I have done it, it is way easier for me to do it in my second bathroom with the lights out and door seals to keep outside light at bay. For my changing bag days I built a tenting insert made from a cardboard box so that the sides of the bag stayed out of the way. A lot easier that way but still a pain down south.