Nice hearing your journeys!
About the MDMA.... I dont know if it a super powerful spiritual tool, but it is fantastic for emotional healing. It really helped me in the past, though I now focus on San Pedro (somewhat similar in certain ways, but with more depth and power then MDMA). San Pedro is amazing though - often very gentle, but if you stick with it long enough it will take you on some deep journeys!
Visions are fun.... Sometimes they are distracting. I think you have a good perspective of knowing the are not the goal though - and I think you might be more likely to experience them if you never chase them. I do know a few people who never have visions ever despite lots of psychedelic work - some people just get information other ways.... Most times I dont have visions, just every once in a while (and dose size doesnt seem to affect that either way).
Hope your DMT experiments go well! And hope you have a nice time with San Pedro!