I'm gonna throw out that it is all individual preference. I'm a little bigger than you and ride a 159wide and love it. I feel stable in all conditions. I borrowed my boys 153 Ride and man what a difference but it is a much softer board too so that also needs to be factored in. His was a lot of fun to mess around on and I might take it off his hands when he gets a new one next year.
But, maybe do to the lack of time on it not sure, I felt less stable as his is a very giving board. It might have been that his being shorter, it took much less effort for the same movement as my board does.
I guess the point is it would be best to demo some boards or borrow a buddies that are different size and softness that compliment your type of riding. Me I ride everywhere and as of now my current set-up is working very well and I don't want to mess with something that aint broke...
-I'm Slyder and I suffer from "Gummer Syndrome"