No sound on this computer so I've seen the vids but not heard them.
{EDIT} perhaps more if four mics on a single bar...
All that sound right.. except I wouldn’t suggest putting all four mics on the same bar
with the intent of mixing them.For the three channel main mic thing, I’d want the side stands higher, like 8’ up or more rather than 4’. And yes it would probably be best to have all three at the same height, although it’s more important that they are all approximately the same distance, which could be accommodated for by moving the center forward and the sides back.
Your 24” bar is not enough spacing for a 3 mic setup on one bar using omnis or sub-cards. That width would be enough if using 3 supercardioids, as long as you could also get the center mic about a foot in front of the other two (like a small directional decca tree), and that is similar to an arrangement I use for on-stage recording of jazz combos with the 3-mic technique- left and right supercards pointed about 45 degrees away from center. See the William charts for multi-mic setups using supercards for specifics on that if interested, but it's not what I would do for this.
If you are limited to having to use the two short stands and 24” bar, I’d probably forgo the 3 main mic suggestion (which I still think is a valid choice and am more than willing to defend) and do one of these things:
1) Revert to two channel with the AKGs in cardioid or subcardioid mode on the tall central stand, angled and spaced based on the Stereo Zoom two channel charts. You could also run your extra pair of cardioids on the same stand as well, but not for making a 4 mic mix which
is likely to have phase problems form the mics not being far enough apart or angled far enough away from each other, but rather as an interesting source for comparison which would be educational.
2) Instead of putting the extra cardioid pair on the same stand, I’d probably place them at the extreme edges of the stage on the short stands facing directly out into the audience as room mics
which can be mixed with the main pair. That’s a standard ‘room and audience mic’ing setup’ which works well, gives a nicely diffuse ambience and crowd reaction and will add a sense of width and depth the stereo pair alone may lack, especially if using the cardioid mode for the main mics.