Aquila1954,
You mentioned your fin is off a bit well I noticed this weekend my horizontal stabilizer is off a touch, and I epoxied it on. I've never done that before and I'm not sure how it happened or how much "off" is okay or not and if I should attempt to fix it, it's covered already! Anyways both of my Riser tips appeared to be the same density but your wing tips turned out super nice great job! As for the anti-vortex wing tips, I think I saw a thread not sure where that a guy built it on his Riser. I know I thought about it after seeing HelloScott do his that way on his OlyII build which is the original design for the Oly. Maybe someone can comment on there usefulness but they sure look cool, I decided against it because I didn't want to deal with covering them. Just being lazy