haha english is most definitely first but my brain is frazzled because of exams atm. having re-read it i could have worded it alot better.
i dont dispute your advice from your perspective of having rode centre on this type of ski all year.
having not rode centred on these skis i cant tell him if its worth it. all i can say is that having rode on mine for the last 2 years at -7 i feel they have been good but would have been better mounted forward from there.
with the weight centre -7 back from centre i think that the balance would feel odd being that far back.
hence my compromise of between centre and -7.