Either way really. Basicly if the swamp cooler makes your room more then 50% humidity ,you should use a dehumidifier.
The ac in the window has invisible exhaust. And it isn't wierd.They are everywhere. I am about to install one in my window.
If I was you I'd use the window ac.It's just easier. And MJ needs a dry climate.Just make sure you get alot of btu's. Like 10,000 in a normal size room. Like 15 square feet. Mine is 8,000 I think. But I have a cooled hood (that would help alot) (But they need holes in the wall,so.)I also have an exhaust fan. But the ac in the window should work fine.