If you've already go your fundamentals then rocker is just easier. But being easier in the learning phase means learning back technique. It doesn't hinder pressing, just the learning of pressing.
Having less board underneath you will basically mean less board to slide across the metal. Less stable. And you will overflex a 144 meaning no stability or lock in a press.
I haven't looked at a board weight range for eons. I've ridden almost everything I recommended you so I just know how they ride. And knowing how they ride those are the sizes for you weight you should be looking at.
That thing I do to escape the world and have fun with my friend