IMO
Yep just go the 8, smaller kites =

, if you live in Gero there will be days you wish you had a smaller kite (6 or 7) however there will be lots of days that you will be happy to have the extra power of the 8 so you can stay on your smallest kite longer. As much as you now love your 12 your small kite will be the one that you want to use all the time soon, I weigh about the same as you and I think it would be used more often if it were an 8.
Tightlines