Ya, I have lots of thoughts on it. I feel you are on the right track. The only way soil nutrients can be taken up by the plant is with water. So if the nutrient is in the top inch of soil as it would be in a broadcast app, then as soon as that top inch of soil dries up, the nutrient source does too.

 Several years ago I asked about pressurizing liquid fertilizers. Seems it is fine to do so and does not appear to be a danger or degradation to most nutrient types. Trick will be getting the nutrient evenly to the same location within the profile of the disk slot. If the nutrient stream hits the sides of the slot in an uneven, or sporatic manner, then the plants timing of locating it, and the nutrient's concentration will vary. IMO.

 My current drill is a JD 1590, 7.5", with the openers moved to aquire the twin row setup. One row on each side of the band. I've been using this system for a few years with various banding tools to find the one I need. One drill row 2" on each side of the band. That makes a 4" twin row on 15" centers. Meaning the seed rows are 4" apart with an 11" isle between them.

 Even if you do not care for the Exactrix system, their website, and owner Guy Swanson, are a huge resource on the topic.

 IMO.