How much do you weigh?
I think gre-969 makes good points. Also, moving up to an 11.0 from a 10.0 on the 155 isn't going to make much difference in earlier planing. Maybe a knot or two at best.
For me on my Formula 160, the difference between my 9.2 and 11.0 sails when it comes to pumping up on plane is about about 8 knots on the 11.0 and 9-10 knots on the 9.2.
I weight 79kg.