It's a trade off between ease and security in jibes and stuff and control in high wind a. For the "pure sailing" with 4.2 and 4.7 you will probably have an easier time with a sub 80 liter board. But overall, that will likely be too big a step down from what you have now.
But between the boards you're looking at I would for sure say Kode 86. In fact, I'm willing to bet that you will even find the Kode 80 easy enough. You'll need to be a bit quicker in the jibes but you will have a much easier time when you start to venture into waves. At your weight, the narrower tail of the Kode 80 will make the board easier to handle. But if you feel unsure about this step, take the Kode86.