Heres the Nm link:
http://wiki.bluegartr.com/bg/Umagrhk
Heres the link to Tiers:
http://wiki.bluegartr.com/bg/Category:Meeble_Burrows_(Sauromugue)
In order to purchace the KI for a tier you must have completed it 1st.
In order to enter a boss fight you must have completed the tier
In order to enter Mega Boss fight you must have completed all tiers.
(On the same Grimoire)
Don't make mistake by swopping Grimoires in middle of runs. iv see it done many times... always know what your books have on them.
All can be Trio easily
Like Sek said above will cost about 1M per run if you go that route, between 200-300k gil per KI.
Otherwise it will take you 25 Pheromone sacks to gain accsess to 1 chance at a 4% drop.
Its not hard by any means, just more of a time consuming with building tiers and hoping you win the lot, if it even drops. But Meebles is fun as hell so its not dreadfull at all.
Id suggest getting TH boon and bringing Thf for sure.