as far as temp goes, whatever temperature you live in comfortably, would probably be a-ok for the cactus (thought it can handle quite a bit of heat for a mountain cactus)

as far as watering goes, its best to err on the side of underwatering. worst case scenario you water-stress the cactus, increasing the alks a bit.  when it starts to wrinkle, water it.  after a while you will get a feel for how long it takes between waterings

(obviously it changes depending how heavily you water it).

idk if it gets subzero in the andes. but i do know that it gets pretty cold there, which is where achuma is from. maybe someone more educated on the climate can chime in. it would be great if you could get them to grow wild there.

but even still just having them in a pot means you can put them out in the summer.

just make sure it get lots and lots of light all year round so they don't get etiolated.

also if you wanted, you could cut the top off one. plant the bottom, then extract one and plant the other.

or do something like that.

or you could get them all to grow bigger and have more to extract (if you buy into that patience being a virtue BS)