if i were to grow myself a peyote trip i'd never graft them. to me, it seems extremely disrespectful towards the cactus' spirit. The accelerated growth reminds me of those genetically modified salmons that grow so fat so quickly they get all kinds of deformations and/or end up barely able to breathe, suffocating.
you can let them regrow (when they not grafted, or when you cut them off the graft and plant them so they grow roots) if you leave the roots and a little underground flesh. i imagine this of little use when cultivated (since it would take another 15-20 years to spiritually mature again), but when harvested from nature it leaves a plant instead of endangering it further.
anyway because of my issues with grafting and also out of sheer simplicity i'd say if you want to experience growing mescaline grow a san pedro, and if you are interested in the growth of spiritual experience (in the sense of: the path itself is more important then its end) i'd suggest devoting yourself to a few peyotes over the course of 15-20 years. i bet they'd really 'root' you.
edit: a third option could of course be to go look for them in the desert.
Also, when you buy say a big '10 year old' peyote from a shop i'd imagine one *very* lucky if its indeed a 10 year old and not a grafted one