If you can be flexible about which day you go to the water parks, that will help. If not, just be aware weather may interfere.
Here's my story: One winter visit, we had a short WDW trip, and were given special passes that expired at the end of our stay. It was go or don't go. We arrived at the gate about 90 min before park close.
It was an unseasonably warm winter day, so more crowded than a normal winter day, but less crowded than a normal summer day.
We made the mistake, sorta, of hitting Crush and Gusher first. That was by far the longest line. We went on almost everything except the shark reef, the wave pool, and the storm slides (they had no line). We didn't spend a ton of time in the lazy river, but we made it part way around. We went on one of the slides twice.
My suspicion is that many folks start on the smaller slides, and work their way UP to Crush and Gusher. If you end there, the line will be short, but if you start there, you'll hit it right at rush hour.
For us, it also helped that we didn't bring (much of) anything with us, so we didn't use chairs or lockers, we just took off our shoes. We had towels in the car, but were mostly dry by the time we got there.
