... the Kahoona is a fine kite but as you get more experienced you'll find at your weight, it will deform and give you the sh!ts.
What will happen is you'll learn to edge harder and the harder you edge and put pressure on the kite, it will start to deform and loose performance. Then you'll wish you had a more stable kite under all conditions and from what I found, bridle kites are not really going to do it for you.
From the kites I've tried, North Rebel remain stable in all but the most extreme conditions and importantly, steering/upwind and feel won't change. I tried the Naish Fly and Draft, 2 good light wind kites but when I started to kite with a bit more aggression, they deform but worse, the steering characteristics and kite feel changed. When a few lighter guys tried it, they didn't get the same results so I figured, the kites just don't suit the heavier guy.
Your boards are good size and as you get more experince you'll want a smaller board. I use a 138 x 43 as my high wind TT. I can use a smaller board easily but the little extra width gets me through the lulls but if the wind picks up, I just edge harder so the extra width isn't a problem.
Keep having fun, good luck.