Destination Wedding In Belize

I`m planning on having a small wedding (less than 30 ppl) in Belize next year. I still haven`t figured out a date, though originally we were thinking Sept. But it seems that is their rainy season. Has anyone been to Belize during the rainy season?
We also were thinking of having it on Ambergris Caye, does anyone know anything about this little island and of any nice and inexpensive hotels there. Any info will be great. I have read the websites of Belize any every one of them says the same thing