I think everyone would want to use the Sigma... I'm just afraid it will push the possibilities weight & balance wise... you can shift the center of gravity only back so far... the question has been asked on their FB a couple of times and not sure anyone got a reply on that confirming or denying the compatibility.
True, I think it's just not of importance to Dave, since he likes his set-up small and not attracting too much attention. But yeah, it would be worth to atleast mention. Exciting you'll be getting yours soon, saw they were a little overwhelmed with how well this is received and are trying as hard as possible to meet demand but can't avoid 3-4 weeks delays for some.
Yeah, that's pretty typical Chinese practices unfortunately, I recommend sticking around on their Facebook to ask questions. Dave mentioned contact through Yanherlin is pretty good, just know that he uses his channel and Gmail userhandle (yanherlin at gmail) for Pilotfly: https://www.youtube.com/user/Yanherlin ). Thought they had a set-up video, but I guess I'm mistaken. I guess you could kinda figure what Yoshihide is doing here:
-- they now also feature a drone-capable version of the H2, with 2nd arm (no open side) and lockdown mode bracket called the T1... (click img > 'Full size')
-- FB info regarding GH4 + Sigma 18-35mm compatibility update:
I love image stabilization on lenses but sometimes you need more stability or a faster lens. I use a tripod, I use a monopod, I've used gimbals. But sometimes I just want more mobility with a small rig and the ability to handhold a shot without looking like a moron with a big clunky shoulder rig. I'm talking GH4, A7S, etc. I love the simple gun stock options, but most seen built of garbage. What works best for you?