I don't use EHU in my tent, so i have 12v ones that plug into cigarette lighter in car, they are obvs not as good as my GHD's but they do a not too bad job, on my thick hair.
Yep, GHDs in a tent, no problem. So long as you don't have the kettle, radio, fan heater and fridge running at the same time then you're not likely to blow the fuse!