esg - Thanks for your interest. In the spirit of simplest possible solutions, this project did start with squared-off wingtips. With later prototypes I revised the angle toward what you've commented on in the wireframe because, with this design specifically, that area seemed unsupported (even though it had a great deal of bridle tension though it), and seemingly useless. After a bit of tweaking, nothing was lost in removing that area, and it now matches more closely the angle of attack that it flies at. Like everything else for this project, if it isn't helpful, it was eliminated. I added, "with this design specifically" because I think a change in angle of attack or LE sweep would surely get a different result, and that squared off is great for other designs.
Also on this subject, I'm a pretty big fan at this point of wide wingtips for the steering characteristic they can have. And, while there would be other solutions, they do a great job of helping the canopy open during relaunch on this strutless design.
Gigi - Thank for the comment / link.
peterheirman - I've never tried, but my guess would be that we wouldn't feel a difference with or without the holes, because I doubt there's a whole lot of lift going on in that area (no pun intended). Would be easy to test by just patching over them, yeah? If/when there is lift, maybe the holes even do something useful for aerodynamics in certain circumstances to reduce stall? I dunno. Just keeping a positive open mind. I hope I don't offend you by supporting Naish, but I've flown a bunch of their kites over the years that I've found great, and truly feel they've done a great deal for our sport by pretty much putting it on the map.