Looking at the many impressive sessions of some WA sailors on the GPSTC, they are using mark II Chris Lockwood fins (creatively nicknamed "Clockwoods"??) with great results and positive feedback. Last year he kindly sent through some detailed information on his mark I designs and I am enquiring if anyone has used the markII's in iSonics (preferably a 2014 iS90 and '13 iS110). It seems that most the sailors (and especially Chris himself) use fins much smaller than convention so I'm wondering if a 33-34cm for the iS90 (with 6.3 & 7.0) and 38-40cm for the iS110 (with 7.8 mainly) would be the optimum size. I have successfully used Select S1 33cm & 34cm Goldwing with the iS90 and a 40cm StingII with the iS110 /7.8 and 44F-hot with the iS110/8.6.

My past experience with his KA slalom fins has been brilliant. In case I haven't mentioned this before I sail open ocean and weigh low to mid 90kgs.

Photo of the Lockwood markI's (I think) - EDIT JJ confirmed these are Mark II's ;