Trying to do it like 2-3 days apart doesn't work.
Tolerance. You only get body numbing and some minor effects, needing bigger and bigger dosages.
The body-stretching/sliding effect. The visual effects. The journeys.
To get those back, it needs at least a 2-week break, it seems.
I don't know how Lilly did this regularly...
If you try to use Ketamine to go into those astral realms, it seems like you still need the tolerance break to do so, attempting it daily just makes it much less visual, though still its possible, if you sort of push it along, but not like with 0 tolerance where you can just IM 60mg and be gone!