How long have you been windsurfing? I had one of the first 115 stypes and it will forgive all your sins especially in chop the only down side (and it's not really a downside!) the boards feel alot!!!! smaller than they are! I weigh 70kg and I sailed a 91 jp FRC for a year and the s-type 115 which replaced it felt as small if not a little smaller. If you have have good ballence then this is not an issue. I loved the s-type, and it's great for steaming past people because it is so easy to sail and it lets you get away with bad technique! Be interested to hear what Kevin has to say. But I think from what you have said I'd go for the bigger one maybe but which ever you go for you'll love it! You won't be able to wipe the silly grin off your face!