By coincidence, I had both these boards (still have the Kode). The Kode 86 is clearly a one class bigger board a few centímeters wider and with a wider tail and of course more volume. For non wave use, I think you will find the Kode 86 still small enough at your weight. Both the Kombats and Kode can take a lot of power and chop. At 5.3 and above I think the Kode 86 will prove a bit easier than the smaller Kombat 79.
But if you want the best possible high wind feel and will not use it with sails above (say) 5.5 the Kombat 79 may be more fun. It is still very effective, meaning that the lower volume shape will still provide good planing and glide through lulls.
Construction wise, the Kode 86 wood and Kombat 79 wood are similar. And both are very fun boards to ride, with an amazing jibe and just a nice feel overall. So in the ends its more a matter of size.