Zoas are extremely hardy and unless your parameters are way off the norm, you really don't have to acclimate. But it's ok if you do. Slow acclimation will help and work with any coral. I can't believe they would tell you that the warranty would be void if you did. That is even safer than just dropping them in your tank in my opinion. However, caution is the word of the day. My practice is this and it is the most full proof measures you can take to keep your zoas happy and healthy during the transition and safe from allow any predators to enter your tank.
1. Buy a cheap, 3, 4, 5 or 8 gallon nano. A light, heater and some sort of cheap circulation is all you need. No substrate. Fill it with tank water from your mature main system. I never even run the nano until I purchase something. I take the water from my main system and fill the nano for a holding period of a week for the corals.
2. Float the bag if you want to equalize the temp. Remove the new arrival from the bag and inspect every single inch of the rock with a magnifying glass. Using dedicated tweezers, pluck off anything that might cause an issue down the line.
3. Using a stiff tooth brush, I rake the entire rock. I mean if it's not a polyp, I remove it, period.
4. Using a syringe, I squirt scalding hot water into each hole in the rock, making sure the hot water never touches the corals.
5. Then I do a fresh water dip with Lugols and FWE for about 4 minutes or so.
6. Invert and swoosh as fast as I can.
7. inspect near an actinic light for nudi eggs or anything suspicious.
8. Then I place it in a Qt tank for a few days of observation.
Taking these few measures will insure that nothing gets into your tank that you will regret later. I know this seems like a lot to do, but it only takes about 10 minutes.
Mucho