At your weight a 7m and 11m would have been ideal but you still have a good set there. You will likely ride the 8m for 80% of summer.
If you really wanna max your low wind time on the water adding a biggish board (I have a 150cm) will add more range (using your 12m) than getting a +14m kite. Heaps more fun to fly a 12m and it is waaayy cheaper to add a board than a kite too. Win win.

Best wait until after next summer before taking on winter kiting.
Good luck.