As I always say, I'm not going to do the math for you - it's simple enough. But, I can certainly offer some guidance.
-- You can't buy a trailer based on how you "think" you will load it. You must buy the trailer based on "loaded up". To do otherwise would be foolhardy
-- Fuel is about 6.5lbs per gallon
-- Water is about 8lbs per gallon
-- Batteries are about 50lbs each
-- Any options you have on the boat need to be calculated in because the listed dry weight is for a bare bones boat
-- Add about 300lbs to 500lbs for ice, gear, 2-stroke oil, etc
-- For safe measure, add 10% to this final figure
Now you have your carrying capacity - GVWR will include the weight of the trailer and that depends on the type of the trailer and configuration.
Don't buy a trailer based solely on price. Avoid cheapies like Venture - they "can" be OK, but their rate of quality issues far exceeds others.
If you're not going to setup the trailer to fit the hull once you get it, make sure you are buying from a reputable dealer.
Get brakes on all axles. Highly consider EOH brakes - espeically if you're towing with a marginal vehicle - but either way, it is MUCH safer.