Yea, that the only direction to go. Start with what you think is the best and then move to what's right for you. Also, the old summicrons hold their value (as most classic lenses these days regardless of mfg) so buying and selling used has little monetary risk when your trying to find what's right for you. I wouldn't know about Madison Avenue hype or test charts regarding the CV or Summicrons, but human psyc and phenomenology regarding GAS I have some experience.
I don't recall losing money on my buying, review and sale exercise.
But the lenses I picked are easy for me to use and hand held at /5.6 and /125 there was not much difference.
But Gary Winogrand did use an LTM Canon on his M4 for some shots.
http://cameraquest.com/LeicaM4G.htm
He used a lotta film.