I lived in AK for 44 yrs until 2002, so I know how huge Alaskan mosquitos are. Unfortunately, I didn't use anything special when I had a quarter-pony mare as a teenager. In WA, where I live now, the mosquitos are wimpy, if they show up at all. I use Mosquito Halt! if I know I'm going into the woods. I don't have any experience with Shoo! as a repellant, sorry.
Do you live in ANC?