Tim, just for giggles I just made a short vid clip of hovering the Trex 500 in what amounts to a wind turbulence tunnel between a row of pines trees and my shop with wind swirling and 10-15mph. With the settings I posted, except I set the VFF back to .15 on both pitch and roll, which really livens it up.
Just wanted to demonstrate that you can make a FBL helicopter hover perfect in Loiter using more VFF and I-gain and less P. It is as close to flybar stability as I've gotten that helicopter to fly. Little bit of GPS drift, which is normal. But I've never been happier with the tuning in this heli with the DFC head.
So don't be afraid to try a little more VFF gain. It won't make it oscillate. It just makes it sharper and sharper and gives both you and the FC more control rate response, the more you turn it up. I'm running more VFF with this heli than I've ever seen anybody use with a FBL, and it works. There's no toilet bowling or anything. It's just about like it's mounted on a post in probably the worst place you can have to fly in. I know for a fact that if I was trying hover my TriCopter there it would dancing around like a drunk bumble bee