I feed my babies in deli cups or the equivalent, but I just pop them in the deli cup with the pink(s) and put the deli cup back in the tub & move on to the next one, and by the time I get to the end most of the babies at the beginning are done with dinner and I carefully pour them out of the deli cup into the tub. I have lots of deli cups and other small containers of the same size for the purpose. Works great, improves feeding success (little babies often don't eat unless dinner is RIGHT in front of their noses) but allows them some room to slither in between meals. A 2.7L tub seems quite reasonable as a home, and the set up sounds fine. Some baby corns are just not gonna eat, it doesn't sound like it was poor care on your part. If you already have BPs you know the basics about hides, water, temp control, humidity, all that stuff.
Dragon666's -- the sandwich boxes sound like a good smaller option. Thanks!
Oh, and Taz -- nothing wrong IMHO with the 20L from the get-go, I just like the smaller containers because I have expanded my population so much!