You can decide for yourself if 24 inch stands would be OK. The rule of thumb is that you want the center of the tweeter (the top driver in the M22s) to be, approximately, at the same height your ears will be when comfortably seated in your listening area. 24 inch stands, plus 19.8 inch speakers, equals 42.8 inches. Subtract the distance from the top of the speaker to the center of the tweeter, I'm just guessing it's around 3 inches, and you get 39.8 inches. Call it 39 inches.
Sit in your chair/sofa/recliner and measure how high your ears are. It works best to have someone else do this cuz you can only approximate where your own ears are. If the that height is within a few of inches of 39", either way, you should be fine.
Keep in mind that the "same height as your ears" thing is only a guideline. The idea is not to have too great a discrepancy between the height of your ears and the height of the tweeter.
