I did Mike Ball's Spoilsport in April 2008, their Fall. Jan thru April is their rainy season , as the new reports of the last week verify. That year they had 25 FEET for rain in Northern Queensland and therefore the viz was not what I expected - about 50 ft at most sites , over 100 feet on one site. Sea life abundant and beautiful.
December should be better. Spoilsport was first class ! Boat holds 24 divers I think, there were 11 divers and 1 snorkler the week I was there. 24 would be REALLY crowded I think. food great, crew great , would not change a thing.
This was the first week of a 25 day trip, so I rented everything. I was really glad to get back to my own gear . I was OK stuff, just not mine.