Agree about the shoes. Here's my breakdown.
Ripsaw falls - Will soak your entire upper body. The front and sides of your shirt will be completely soaked.
Popeye - If you go under a water fall, you'll be complete soaked like standing under a shower. When you get in the raft, put your seat belt on, then put your shoes and socks in the middle compartment. You have to walk into the ride with shoes on, but once in the raft, if you get your seat belt on, you can put the shoes in the middle and the ride ops will let it slide.
JPRA - If you sit in the back row, it's only a little splash.
If you are staying onsite, then wear older shoes, and plan on going back to the hotel after getting soaked. Or you bring a change of cloths and put it in a locker near the front of the park.