Hi Spark09,
You wrote ;
Quote;
' I modified my wings with winglets like the Wind S Pro GFK version the bubble tips these seem to work better than the flat ones used on the Oxai Citrin. I also have them on the tips of the stabilizer for rock solid flight in windy conditions.
I also widened the TE of the rudder by almost 2 cm. '

I wonder is the 'bubble' actually giving a subtle 'toe in' effect ??
It is the only reason that I can see for it being noticeably better.
Interesting !!?

Brian