I'm thinking about getting a portable jump starter to take on my 306 Grady with twin 300's when fishing off shore. I go out 40+ miles and although I haven't had a problem, I'd feel better having one just in case. They come in many different amp sizes; I've seen 100 all the way to 1200. Not sure what size would be needed to jump these motors and if anyone has a brand that they have used and like. Any other feedback would be appreciated too.