I'm glad that you noticed a difference in temperature, that's promising.
I'm only going to paint the outside of the hull
(all of it mind you, eve3n under the water), but the people i spoke to said it can be used on both inside and outside to get maximum effect
With regards to thickness from what i have read you only need it in two coats and going thicker doesn't benefit that much.
Thanks for you reply anyway, it doesn't seem that many people on here have used this stuff