I actually got the idea from a guy that I used to compete against in a lot of events. On his big smoker, he used fiberglass insulation on his smoker sidewalls and lid, and then covered it with brown aluminum house siding, with a drill and aluminum tap-rivet install He could remove or add them as he wished, to account for colder outside temperatures so he wasn't burning up a cord of hickory to do a cook. I did the same thing on the weber, using unpainted aluminum flashing and uncoated sheet metal screws in predrilled holes at strategic points. Flashing is made to bend, and it is fairly easy to trim out some relief points and form it around the weber body and lid with a ball peen and dolly. Make sure you don't use something like tin or galvanized sheeting, its toxic when heated. Then I sprayed it with BBQ black paint so it doesn't look quite as redneck, and I was good to go. In truth, I had a summer weekend and felt like farting around in the shop - the moving blanket I think worked about as well, and I used it for quite a few sessions before I caught it on fire. for that, I just cut a whole in the top for the vent and temp gauge (never, ever cover or close that vent unless you are extinguishing the coals) and draped it on the same as you would a grill cover. It was short enough that the thing could draw in plenty of air underneath, but was one continuous insulation cushion over the grill. With either setup, I'm running about 12-15 coals on one side of the grill, with the exhaust vent on the other side so that it draws heat across the meat, the bottom vent at around half pull, and replacing coals about every hour and a half with well burning coals from the chimney. Turn the meat around when you add coals because you will get some radiant heat differences from the coals. Temp can be kept right at 225 by tiny adjustments of the bottom vent, which is the temp I've found to be the best balance for speed and keeping things tender. Baby backs can get done in about 3.5 hours, St. Louis ribs about an hour more. I peal the membrane and soak in apple cider with a tablespoon or so of bourbon overnight, then dry them off and use a dry rub that's a little higher sugar/less salt than a standard rub, because there's so little meat here that a normal rub is going to dry you out and make the meat overly salty. Leave those ribs out about an hour so that they are coming up to room temp before you put them on your grill, which should be running about 250, especially if you have several racks - cold meat will mess with your temperature regulation quite a bit. Watch the temp close for the first 15-20 minutes as the meat comes up to temp. Don't open the damn thing until you start losing temp because your charcoal is used up. When you add your already hot charcoal, throw on a SMALL handful of soaked hickory or applewood, or one fistsized chunk, already burning well. Because you never get the thing over about 250, you can use a high paprika rub and not end up burning it and creating bitterness. I put a pan of water on the coal grate to keep the coals off to the side and help regulate the temp. That's about it.
Edit to add: I just looked at that smokerator thing. I'd be a little worried about the ability to keep the coals running and how easily it would be to add fuel if needed, but that thing looks like it does pretty much exactly what you would want it to do, looks like an easy and effective solution, especially when combined with a little insulation.