As far as the amount of 299E goes it really depends on the number of coats and how thick the paint is. I would say roughly about 1 gallon maybe a little more for that size boat with a few coats on. Like I said it really depends on the thickness so you might need more.

As for the application of any paint really, it is 60 degrees. And it's not 60 degree air temp it's 60 degrees surface temp. The hull of the boat could be 10 degrees lower then the air if it's in the shade it could be even more. I think that is a big problem people end up doing.