I agree with the above - go with the 14.
The rises do have tremendous power and people who have been riding for while can get the most out of a smaller kite - but when you are learning you want slow, steady available power.
For a second kite, people usually do not go with more than a 4m split - so a 10 would be a better choice than the 8. And will get you going early and through the 20 knots range.
Beware the upper range of wind you mentioned until you know what you are doing and a confident rider - things happen much faster and with a lot more consequence in 30+ knots.