I was careful to state that the prodrugs WOULD have different pharmokinetics, if you bothered to read my post.
So yeah, the prodrugs being just that will not be instantly converted to an active and so will have different pharmokinetics and so would feel slightly different (delayed onset, slightly lower peak plasma levels and slightly longer duration).
But the different amides are a lot harder to spot. Tim Skully produced the (R) sec-butyl amine homolouge of LSD for over a decade AS LSD and nobody ever suggested it was not LSD. It actually has a slightly higher 5HT2a affinity but it's pharmokintetics are just about identical. I know a large Italian operation was producing lysergic acid 3-pentyl amide and again, sold it as LSD. Again, they are at it for over a decade.
Later a smaller producer made lysergic acid (S,S) 2,4-dimethylazetidide (higher affinity again) but nobody noticed much and I argue would have mistaken it for LSD unless told.
So when people don't know - they don't NOTICE. But if you buy ALD 52 or any of those increasingly bulky amide prodrugs, they are going to become increasingly different to LSD. I still believe that if nobody knew, they wouldn't
It's such a subjective drug that no 2 trips are the same. So it would be nice to try a double-blind study with control, subjects given LSD, subjects given one of the different amides (sec butyl or 3-pentyl amide). I very much doubt people would notice. Obviously animal models showed them to be the same, but it's not a good topic for animal models.
I should add that the NBOMes offered a new class of highly potent 5HT2b ligand but they turned out to be hazardous. It would be nice to know why.