RE: iS145 vs. iS133 in 8-14kts 7.5-9.5 sails?
Bottom line - at your weight with those sails, you do not need the iS 145. I have a 133 and from a slalom perspective that is the biggest I would go. The 145 seems IMHO more related to the previous Free Formula and F-Type and will feel a very different board than the 133.
I previously owned a Free Formula which was an absolute joy to sail with 9-10.5 meter sails, but I would not consider sticking a 7.5 in it (although I accept its perfectly possible)
133 all the way!