I thought I could add a thing or two since I'm 85kg and use Kombat86 a lot. I haven't sailed K79, but I've tried similar boards in that volume range (fsw). I think that at your weight, Kode86 is much more allround board, better for 20 knots and 5-6 m sails, and better for lulls/easier to bring you home schlogging if you might need it. I use it mostly in solid 18-20 to 28-30 knots, but it goes more now and then. It can take overpower very well for its size as Ola says (read gusts of 30+ with 4.x sails). I guess K79 makes more sense only if you sail mostly in very windy, very consistent spots (Tarifa, Columbia gorge?).
Good luck with your K