Pitzips are great if the weather is cool and you are warm. IF the weather is warm and humid, the won't help as much.

Given the weather you are likely to face--warm and humid--I wonder if a rainshell is even worth it. If you are hiking in one, you will create a sauna inside from your own perspiration. It might be better to simply get wet from the rain in a quick drying synthetic shirt, and pack a second shirt to wear once you are somewhere dry.

I have a very lightweight rainshell for cycling in California. I have never put it on to stay dry--because the minute I put it on, I sweat it up into a steamroom. But it does keep me warmer in a cold rain.