Sony a6600/70-350 lens.

Anybody is using Sony D6400 or D6600 for BIT. What the best setting would be, other than the basic used for all brands.
I bought the 70-350 lens and plan to buy the 200-600 lens later. I have the A6600 camera.
Thanks.

BIT? I guess you mean BIF
Check out Mark Galer's YouTube channel to learn how all of the different AF modes work (and everything else on Sony cameras - you can look at a9 and a7R4 videos as the systems all work the same way and are set-up the same way using the same menu structure).  My suggestion would be to use continuous AF, Tracking: Expand Flexible Spot.  There are many that will recommend using Wide but the problem with that is that it picks up the nearest thing and then tracks it and that is often a wingtip rather than the head.  Do note that f/6.3 is a fairly slow lens and the AF system will not be as fast as it would be with a faster lens.  The 200-600 is also f/6.3 but it is significantly faster.  But the 70-350 should still work well with predictable flyers.

Thanks, E.J. BIF, that is.
I will check out those videos as well.
My best BIF lens is the Nikon 300 F 4.0 PF with either D500 or D850 right now but mostly for predictable flyers.
Many times the 500 f 5.6 works  well, but nothing beats the 300 f 4.0.
Probably there is but I don't have it.

Karl Egressy wrote:Thanks, E.J. BIF, that is.
I will check out those videos as well.
My best BIF lens is the Nikon 300 F 4.0 PF with either D500 or D850 right now but mostly for predictable flyers.
Many times the 500 f 5.6 works  well, but nothing beats the 300 f 4.0.
Probably there is but I don't have it.

The 300/4 collects twice as much light as a 500/5.6.  If everything else is equal including AF motor capability on the lens, it should focus quicker and track better since the AF system is receiving twice as many photons.  Similarly, any 300/2.8 kills any 300/4 for AF performance for the same reason.