Thanks a lot girls. I've actually designed a vest before but it was for my daughter and only needed about 30 or so stitches each side. I followed a pattern and didn't like it so I did the whole thing again my way and loved it. Fitted really nice on her.
The thing that's putting me off a bit is the number of stitches that I'll need each side: 85/80! It will take me about a year to finish it.
Some woman told me I should do it all one piece leaving an opening for the neck. If I do decide to go ahead with it and it comes out wrong I might give it to someone rather than undoing it.