If you find a shop (or rider) that's willing to let you try boards, try talking them into letting you try a Kode 74 too. At your size, that might be even better.
If you don't want to spend as much, you might also look for an Acid 80 2006-2008 (or 74 07/08). All good boards on flat water too and all of them will handle 5.0 easily be easier in strong wind than the wider Kombat 79.
With all these boards, I think you will fins the general feel is rather similar to your Kombat.
A 28cm fin seems a bit big even for freeride with your smaller sails. I think you will find that a smaller fin makes the board much easier to handle.