Sect leader's max qi is 3962, and was fed a spirit stone, qi regen pill, and purity pill just before the attempt, which took place around midday to maximize yin/yang bonus. Got about 2/3rds of the way through tier 7 before her qi ran out. Wasn't able to score any Earth Flux beforehand, despite numerous save-scums just before the adventure event at the place you can harvest it. I suspect the game rolls the adventure event shortly before it pops up, or else there's some other anti-scum method in place. I saved just seconds before the popup, and after a few, different(and useless) events, it just kept giving me the "enjoy mortal realm/wreak havoc in mortal realm" event.
Events are decided ~3 days beforehand, so if you want to save scum you need to go at least 4 days back. Parts of the events are determined when you actually do them (eg. what roll you get on it, what rewards you get for some, what exact enemies pop up to murder you), but the type of event is determined long beforehand.
I think its different for dudes you send on adventure (as obviously adventures don't last 3 days), and save scumming should typically work there, although as EuchreJack points out you flat out can't succeed at getting earth flux without a Fire/Earth cultivator.
Said room is a 5x5 square with igneocopper floor. A cushion in the center has three displays with beast blood surrounding it, and several displays 3 tiles away with spiritwood. The corners of the room have ice bars to keep the room survivable, especially for any outers who might be doing chores in there. Not sure what else I can change to make it better.
As Micro says, not sure how much spoilers you want... but basically you want to stuff as much element appropriate qi gather in the room as possible, the more the better. Also as Micro says you need to wait for 5 full days after dropping the last thing with qi gather down for your cultivation room if you want to get the proper bonus for it.
Note that it being element appropriate is more important than the qi gather. If you stick a wrong element thing too close it messes up the element which is worse then the qi bonus it gives.
(maybe take a look at a giant ginko if you have one).
All range 4 stuff only has a element range of 3, which means you can stick them at range 4 and they still help a great deal. Similarly, most range 5 stuff has element range 4, which means you can stick them at range 5 and they still help.
However this notably does *not* apply to giant ginko, which has both a qi and element range of 5 and is thus useless for anything besides fire cultivating (which needs wood element).
Unfortunately, I missed the highest point of the season(Earth law, so "end of season").
I'll just throw
this super hand season breakthrough guide out there so you can just know ahead of time when to watch for breakthrough so you don't accidently miss it.