thanks for your hints. Here's some more remarks.
Framerate: for us, the framerate was stuck at 40-55fps no matter whether USB is running through the Vive or directly into the PC. Tried different cables, different ports, different lighting conditions, and different Leap Motions. Only after uninstalling and reinstalling the whole Leap software stack, we can get 115fps both for Vive and direct USB ports, and it sometimes (without clear reasons) it goes down to 55 or even 22-25.
Any way to control the behaviour of when Leap goes into a lower framerate better? Sometimes, the framerate seems to get "stuck" at a lower rate and never gets up again, even if lighting is pretty dark. Leap has to be restarted to get to a higher framerate again...
Robust Mode: we'll leave it off for now, but so far it was necessary to have it on to get somewhat reliable performance for trade shows etc., where lighting conditions can vary greatly. Can you explain a bit more what this actually does? More interpolation/filtering for sure, but what else?
Two Hands: any eta on improvements in that area? Is "upcoming release" more like weeks to fix these blockers, or more like months/a year?
Extreme Poses: I strongly believe this should be up to the application developer. Any way to control that behaviour? Otherwise we'll have to "hack" it on top of the existing software implementation (just keep a hand displayed in the last known position if it's not found anymore), but I'd very much like to avoid that and tweak some numbers (even if it's registry changes or whatever).