Trying to learn the skill of BIF photography on my 7D and 100-400L or 70-200LII/2.8. Have been practicing on several herons that frequent here. It's a lot harder than I expected.

Most of the shots (>90%) are totally worthless OOF blurs

Starting to get a few almost acceptable shots which I will post for C&C. For those that are proficient, what settings do you use? Things like (on a 7D) AV or TV mode, what autofocus settings (zone, AF point expansion, etc), metering setting, etc? I try to limit ISO to 400 but that means wide aperture (shallow DOF-blurry) and/or slow shutter speed (again, blurry shots). Maybe I need a 5D3 or 1DX

Thanks for any suggestions. Here are some of my better ones from past 2 days.