Visages are very easy to come by: once you gather your party, do 1 or 2 reives in Ra'kaza and you'll get serveral visages. Tier iV visage seem somewhat common too.
The drop rate on the KI is relatively high (about 15% chance to get it). Instead of doing high-tier body runs (1hour), do several tier 1 runs (takes 5~10mn only). You also get wings and sometimes stones+2 doing these runs.
This week-end I did about 30 I/I/I run (5~10mn each), farmed all the visages on our own because they somehow cost 400k on the AH (its garranted from reives...) We ended up with ~30 KIs among 6 people, so 1 full +1 set per person. Almost every run someone had a KI, and im not counting the wings we got.
A quick walkthrough for the I/I/I run is:
go straight into the umbril room. 6 umbril +1 NM +1 coffer=15~20 points.
Go further west there is always another NM. At this point you are 7-8 mn into the run and have ~20~25 points.
Go back into the umbril room, mobs start repoping. Once you have 30 points you see what you'll get from completing the 2nd objective. If you get garbage, exit. You can still get the KI from clearing obective 1, and from what I saw its not much lower drop rate then secondary objective.