I just farmed this from the Efts in Bibiki Bay (levels 33-36 or whatever) and haven't seen a single one drop in about 2 hours of chain-killing (kill one, immediately switch target to another). It's 3:30am and I'm giving up for now. The drop rate may be EXAGGERATED at 2.4%. To give an idea of how many I've killed (this will be ball-park), I have received 18 Eft Skins (estimated 7.5% drop) and 13 Lizard Eggs (estimated 15.9% drop). 18/.075 = 240. 13/.159 = 81. Those are obviously two extremes, either showing the drop rates to be wrong, or I'm getting luckier on the Skins than I am on the Eggs. Either way, average them out to 160 mobs. Given that estimate, I should have AT LEAST 3 skins by now, if the drop rates are accurate.