I'm fairly sure LSD doesn't cause as much serotonin downregulation (though I could be wrong). At least it doesn't give me as bad of a comedown so I assume it's less brutal on your brain. Tolerance might be an issue, as the mechanisms of action do overlap a bit. I don't think it would stop you getting high, but you might need slightly more to get desired effects?
Never done this per se but I have taken mdma after DMT. I reckon taking mdma the next day would be a bit like when you smoke after tripping and it feels like it brings back a bit of the trippiness which is kinda cool. I imagine you'd be quite exhausted by the end of it tho lol
