Hi Elise,
I would probably use one of the thinner protectors that use a waterproof/breathable membrane. I like them because overall they affect the feel of a mattress less than other types of protectors and have a good combination of waterproof qualities and breathability.
There are a few specific examples here and you can read about some of the protector “tradeoffs” here.
Congratulations on your new mattress … and I hope you’ll let us know how you are enjoying it when it arrives and you’ve had a chance to sleep on it for a few nights 
Phoenix