Yeah they were a nice change of pace. Every step with the tops was stressful because you could ruin a slab. I think the base will go quicker and messing up something up won't be as tragic as a slab. Glad I didn't make the jig as it probably would have taken as long to make as just cranking out the dogs with bandsaw and edge sander. Milling legs and rails today.
Set up in houses I work on, I use a 3 hp DC with no blast gates catching the table saw, jointer, and that miter saw. I built that box just as a prototype thinking that I might need to close up more of the opening, but it works great just like it is, so I haven't changed it for seven years. There is a 1/2" wide slot at the back bottom of the box that opens into a plenum with a 6" outlet at the bottom. If I changed anything, I would make that slot 3/4", but it works fine like it is. Sometimes sticky sawdust (Heart Pine, and Heart Cypress) will block parts of the 1/2" slot. It really does keep all the fine dust out of the house we're working in. Here are a couple of other pictures from the sides, already in the gallery here.
I guess I was going to just do the same thing as I did with the base. The upper cabinet has the same configuration as the bottom. Just narrower. I thought about pocket hole screws but wanted to minimize the visible pocket holes. The plan I'm using calls for using dowels but I figured using screws would be stronger than dowels.