I'm eyeballing it, but wouldn't 6" elevation get both mids clear of the sofa arm?
I kind of freaked when you were talking raising your speakers by 24" as that really throws things way off-axis vertically, but seems like you don't really need that much to clear the mids.
I think you can compromise on a shorter stand.
Alternately (because you may be wanting the speakers more at the elevation of the TV screen), you can elevate them 24" but you'll need to rig a way to tilt the speakers downward so your ears are on-axis, and people in the seats closest to the TV would be well below axis.
I have a pair of speakers elevated using black (actually the color is better described as charcoal) Yoga blocks - cheap, flexible (4X6X8 gives variable heights to experiment with), and don't attract too much attention. If you wanted 6" elevation using these, I would use 3 on each side in an "I" formation (if you just have the top and bottom, there is a chance that a solid hit from a vacuum cleaner or dog might roll the Yoga blocks, but the one positioned 90 degrees in the center would prevent that).