Iceland is a weird cold place, at least in the winter. :S
I usually mixed ACV with water. Dilution would depend on how much ACV I thought I needed. Never sweetened it(didn't really hate the taste), but I always drank it through a straw to protect my teeth.
Personally I would start off with very diluted and then experiment with stronger solutions if you feel like it is too diluted. It's a bit learn as you go along.
I just got some, SG,
and mixed (as per the instructions on the both)
2 TBS in a cup of water (with a little maple syrup).
Still darn sour:)
Will see how it goes...thanks!