The settings you will make are the ATC_ACCEL's for pitch and roll. The default of 110000 is usually too fast for bigger helicopters. I would suggest trying those at 72000 for a 800 and see how it acts. You were mentioning the quick yaw response you noticed in my one vid on auto-flying. You can play with the ATC_ACCEL_Y_MAX as well to tune that smoother for your camera work.
The other one is RC_FEEL.
I don't know that I'd use expo in the radio for pitch and roll. Not unless you can flip the expo out when changing flight modes. Right now you might like it in Stabilize, but in Loiter you don't really want much expo in the radio. Loiter is more of a sluggish, stationary, hovering mode designed to precisely position the helicopter slowly, and it's not really that good for actually flying it. Your stick response will become really bad in Loiter if you use expo in the radio because the center stick curve will be too "flat".
Altitude Hold is an excellent mode to have the autopilot manage collective while you fly the helicopter in the horizontal plane. And you should have the same response in Alt Hold that you have in Stabilize.
If you want flybar-type flying with only rate, then you can use Acro. Personally I do not feel that the electronics and software do a good job of replacing a flybar - it's just not anywhere near as smooth. But if you are used to FBL units in rate mode you will probably like it. I myself hate it the way I have my DFC tuned at present, so I don't use acro at all. I use it all the time with flybar when I want to switch the FC completely out of the picture.
Oh - I had sent you a photo of the landing gears I use on my bigger heli's that have enough ground clearance to carry a gimbal-mounted camera, and bolt-on attachments for different payloads from aux fuel tanks to tether drops. If you want more details on how to build those just PM me and I'll send you the details.