I use Dunlop Tortex 1.14mms for my electric guitar. They are not hard to use at all and I find them better than light picks because I get more control of where the pick is going.
My brother has the same problem with hitting other strings. He has a problem concentrating on it though. It's like a hand-eye co-ordination problem.
Keep practicing with different kind of picks and it will work out.
I couldn't use a pick at first but I didn't want to use my fingers and kept at it and now I don't have to look where to pick, you just know.