I found the best place for this is The Adonis Baths, Trial 2. Surround the Little Sister with Trap Rivets, use the Decoy to throw them off your scent whenever you need to load up on ammo - hack the machines before you start the gather of course.
[UPDATE] I got 100% ADAM on my 2nd try on Adonis Baths, Trial 2, but got it on my 1st try on Pauper's Drop Market, Trials 1 & 3. For 1, I surrounded & spammed the Little Sister with Cyclone Traps. For 3, I surrounded the sister with mini-turrets & spammed Insect Swarm.