Misters are awsome. The less humidity you have the better they work. The other thing I have found with them is that you can have to much a good thing. A fine misting spray can actually be more effective than a high volume of spray. I just got done building a new mister system for all of the pens in our barn. I found that our local ag sprayer dealer had all of the parts I needed and it saved about two-thirds of the cost as apposed to buying ready made misters. I hope this helps you out.
We have the Artic circles on our fans and they work great, we only use 2 mister tips. We also use a mister line in front of a row of fans, we have a Sullivan's Ice Box attached to it, we fill with ice and add water so the mister blows really cold water. The key like Stumpy said is to fine mist the calves without having a wet mess, you just have to play with it until you get it where you are happy with it, we have also done it on a timer system so they get almost dry and then it kicks back on.
For the equipment you can't live without thread, in the summertime this would come close to the top of the list!