A/C opinion

I have started on my build yet(still waiting for delivery) but I was camping this weekend with a friend that has a CT. He has a single hose portable and even though he was comfortable I felt is was a little warm inside. Weather 88degrees, cloudy. He gave me a second single hose to use in my built, but after seeing his I'm going with a dual hose. It gets hot here in South Carolina. I'm not interested in a window unit. I was looking at the WHYNTER 12,000BTU dual hose units on Amazon. Can't find any units locally. Has anyone used this brand, and if so what's your opinion. Can anyone recommend another or better brand and a source for it. CT is 7x12x6'6". It will be factory insulated. Thanks for all your input. Have read from page 1 to current trying to learn everything I can about conversions. I know there's a lot of opinions but one can learn from them. Thanks again.