@Ollie
I understand that it is difficult to give a final conclusion but what would you advise me to do if I do not follow the route of investigation with X-foil or wind-tunnel-tests.
Thinner or thikker or equal thick tip section?
The generality that thinner symmetrical airfoils stall at higher angles of attack than thicker symmetrical airfoils is not true in all cases
So you agree on the article that in general a thinner tip section is better?
I would apologize for the fact that I'm perhaps a bit persistant but I can not decide myself on this point and would like to leave the choise to you.
Thanks,
Hans