Aw, that's really hard but great news on them taking to the tray feeding. I'd be interested to see a photo of the type of tray you are using.
We tried to bottle feed the runt of Lady Penelope's litter, but he would not take to it, not even after quite considerable attempts were made to entice him. We put him back with the family, where he seemed happy, but found him dead yesterday morning. The dish I also tried feeding him from was a disaster - he just ran over and over it, tipping it and so on. hence my question over what you used. With 16 of them to feed, that's some achievement. WELL DONE!! 
This is the bit I found a real problem too, and I only had 2 to hand feed. Got worse and worse as they got bigger. Whatever two trays or dishes I used, both would make a bee line for only one dish, fight, push and bash the other out of the way, spill the whole thing, and then both would go and do exactly the same thing in the second dish. Incredible waste of time, and milk, and re-mixing time. In the end I had to physically separate them, but they still tried their hardest to get into the same small space at the same time, rather than each going into their own compartment with one dish each. I too would love to know how you are managing with 16 !!
