Re: Section ID recommendation?
Drop Charts:
http://edenserv.net/dropsOran and Whitill also have Lame D'argent drops from Dorphon and Kondy respectively.
Oran additionally has Syncestas also, and I think Oran has reasonable Ep4 drops too (Limiter, 101, Fanatic, 502).
Skyly has added benefit of SJS, Red Sword, Chainsawd, and Heart of Poumn (if you're a HUney), which actually is fairly good thanks to being a high-damage dagger rather than a claw.
Olga, like most other bosses, does have high drop rates - between the frequency of monomates and meseta over no drops at all, I'd say that the 1/32 rate is a very good rate, and more likely than not he will drop something (granted, PGF is still a little under three percent, but that is a very good rate as far as PSO drops are concerned). I personally am not thrilled with Viridia however...my biggest draw to it would be Nei's Real, but the rates of that are so low it's not worth it. Pgf is nice and all, but you don't need to make another Viridia just to find one.
Redria has the obvious ease of finding Lavis, meaning hit Lavis is certainly possible, but if you're doing dedicated hunting for one thing, it may be best to just ask another player with the right ID to host Lavis finding sessions. It does, however, allow for easy addslot hunting and the highly desirable state/maintainence on top of that...
Whitill has some decent drops, but many of them seem more RA/FO (Ignition/Guld/all Ring Shields from EP1&2 bosses). I am not sure it would offer much benefit over other classes in terms of raw drops for a HU.
Purple is guns and some FO stuff considering it has Pwand, so you only would need it if you really need a Fanatic assuming you only play as a HU (however, it is a pretty decent class in terms of drops). Pink is an obvious FO class. Green is good for RA, Blue has Asteron Belt, Yellow is probably the only ID I am really unfamiliar with.