Discus Winglets

Hi Folks,

Two questions

1) Anyone out there know how to check the alignment
of winglets that have been retrofitted to a Discus
(CS if it makes any difference)?
I believe this is fairly critical & if it's wrong then
I'm better off flying with the 'normal' tips

2) Anyone out there have access to a study done in
the early nineties, by David Colling I think, on turbulator
tapes for Discus Winglets?

Thanks

PF