1ml syringes - anything bigger is really hard to be accurate with. Little and often - you need to feed more than a mum rabbit would as the milk isn't as rich. Be really careful to feed a drip at a time, you don't want them inhaling the milk - it might take a few days for them to get the hang. If you haven't got milk to hand start with plain water to keep them hydrated. You'll also need to stimulate them to go to the toilet at that age.
Interested you say about toileting -
I have heard that this is not necessary in rabbits in the same way as it is in dogs and cats - and from observation of mum feeding babies they do not seem to do it - just feed and leave.
we did not do it when we hand raised Pippin (or Sunshine - but she is a hare so maybe different again?)
However your knowledge of rabbits is pretty unsurpassable so perhaps they do need it!