get your pruning done before they bloom and you are ok. water sprouts can be pruned anytime. again over 1\3 cutting and your trees will go into vegetative stage and your fruit production will be greatly reduced. Remember heading cuts will produce more vegetative growth then thining cuts!!
I pruned mine in March, bad thing was the flies were out already. I noticed after I pruned them the house flies were landing on the cut-off parts of the tree I'm guessing to eat the sap. I hope they can't hurt them.