Thanks for these comments. I have owned the 24 at least three times, and always reverted back to the 21/28 instead simply due to the "look" of them... In the end, I think I will do as you do for your 2 lens kit, just go with the 28 and 50 and call it a day. IF I need wider for a scenic, I'll shoot multiple frames and stitch them later.
The reality is the M lenses are so tiny that it is unlikely I will ever relegate myself to just two -- like Charlie indicated, my 2-lens kit probably will be the same as my 3 lens kit: the 12, 21, 28, 50 and 73 Hektor