ralph, first of all, i had the m3 sapphires (at clayton’s suggestion when we spoke, and i was debating x vs m series, he suggested the m’s) - clayton is a great guy btw, responsive and helpful, truly wants you to be happy, i really wanted to make these work for me
second, yes i did have 5 ft behind (to front wall), 3 feet to sides... i have had maggies and quad esl’s, still have the quads, know the setup drill
third, as for amps, in the year i had them, i tried many many:
linear tube audio zotl40 ref
audio research ref 75, vt50, vt100-2, 100.2
belles sa-30
hegel rost, h190, h390
cary300b se-i
sony ta1-1es
audiosector patek se
... so i tried solid state and tube, high and low power... gave them every chance...