RE: Kombat 107
The Kombats are very easy to sail boards only a tiny bit more technical than the super easy carves. So, I definitely think a Kobat is a nice next step and since they really rip in waves too you can probably keep it for a long time when you evolve as a sailor.
The tricky thing is sizing. You don't mention sail sizes which makes it even more tricky. I would say that despite that you are coming of bigger boards, you are probably better of with a smaller Kombat. Even the 87 will be a full floater and be far easier in lots of wind. I don't think it will be that much more dificult than a 107, at least not if you nail most waterstarts. You will get more "reserve" with a 107 for that jibe practice, but the Kobats are so super easy jibing boards that I personally think you will quicly learn that also on a smaller Kombat. If you still worry about going this small, get the 97 as a compromise. However, if you intend to use very large sails on this board, you might need to step up in size anyway. At your weight and skill level, I would say the 87 goes up to just above 6.0, then add about half a squaremeter for each board size. When you get more used to the board, you will be able to effectively load it up with a bit more sail. I'm 69 and easily sail the K87 with a 6.3.