In any case, I can add the additional vertical supports (I bored holes on the drill press and used screws to attach them) and added some finish on the bottom. It's probably not necessary, but every now and then I fight my perfectionism and completionism. Once I turn this right side up, I do not plan to ever see the underside again.
Once it's flipped over, I can glue in the grommets. Now it starts to look somewhat like it's supposed to.
Note that the four "interior" holes will not get grommet inserts - there will probably be a lot of wires, including thicker power cables, and I also want airflow. The outside grommets are what Amazon calls "red bronze" and will have inserts. Also, the black plastic grommets in the center channel cavity will get inserts as they are potentially visible. In any case, it's now time to attach the top.
My method for attaching table tops is something I came up with and refined over the years. It has served me well, though it might be a strange idea to some. Let me walk you through it.
1) Scrap pieces of pine (stretchers, I guess, for lack of a better term) are cut to fit inside whatever gaps are available in the top of the piece.
2) Pocket holes are cut to attach those pieces to sides, dividers, back, and face frame as necessary.
3) Holes are drilled for screws with spacing allowed for expansion.
4) Dadoes are cut on the opposite side of the pocket holes (in this case, at 5/8" width to accept Lee Valley #14 expansion washers).
5) Expansion washers are glued in.
The pictures show both sides of the stretchers, the washers attached, and the stretchers installed in the cabinet ready to accept the top. The top can expand about 1/4" in either direction (depending on how well I center the screws) which should be more than enough. This is going from my shop about 12 feet to the wall, but the difference here is that it will contain electronic equipment and an electric fireplace. Even with a built-in cooling fan I expect more than average wood movement. Note that the configuration of the stretchers is somewhat unique - ordinarily I would try to put one all the way in the back (two instead of one in the middle, as it were), but I can't go all the way to the front since I don't have clearance to install fasteners in the very front and I need to leave the back open for the fan. In any case, I use FastCap PowerHead screws to attach the top (really good for such applications). Here it is all put together.
I also had a chance to make some shelves. I used 1/2" prefinished maple plywood (bought online with free shipping from Home Depot, not bad) and prefinished iron-on edging. The nearest size I could find was 3/4", so I ironed the edging on, leaving the shelf a tad wide, and then used a router to trim the edging down. It took a few passes with a chamfer bit, with the last actually chamfering the edge slightly. They turned out pretty smooth, considering they are shelves.
Now I have to do some grunt work. In my old house, I learned that an electric fireplace will take almost all of the juice on a regular 15A circuit. It doesn't need more than that, but it will hog it. I had to run a new circuit, so this meant trenching the wall, running wire, and installing an old work box. It's since been repaired, taped, mudded, and spray textured (at least to where it will be visible). I really, really, really do not like drywall work.
Next up are the doors. I have actually already cut them and just glued them tonight. They are in the clamps now.