I have the 90D, and I've had success with f/8 1/1250 ISO 200 with a Tamron 18-400mm usually at 400mm. I use a range of f/8-f/11 and 1/1250-1/1600 for birds in flight.
I have the Canon 80D with a Tamron 150-600mm lens which isn't the best lens for bif but I generally use manual, AUTO ISO, between f/5.6 and f/8, depending on the light or the dof I want and I set the s.s. between 1/1600 and 1/2500 sec., depending on the light. On bright days I'll go up to 1/2500th. also, I have the camera set to AI Servo and 9 point autofocus and exposure compensation of +1, plus or minus depending on the light. I recommend just playing around with the controls a lot and you'll get to know your camera very well.
I've got the 5DmkIV which has a pretty similar AF system.
Generally I use case 1, or case 5 for small birds. Manual exposure mode, auto ISO, shutter speed 1000 or greater, f8, CWA metering or partial (very occasionally spot). For focus points I tend to have them all activated for BIF, but occasionally I'll have them all activated with a single initial focal point, sometimes I use 9 point, very occasionally single point. EC as appropriate, max ISO 12,800.