Experienced photographers with Canon series II L-lenses will recommend leaving Canon's IS active during 100% of your usage. Experienced photographers with your specific lens model will recommend using IS mode 3 during 100% of your usage. To capture blurred props, you'll need to be around 1/100 second on the shutter for helicopters to around 1/320 sec for high performance prop planes. These situations are where your $1800 ish investment in Canon EF lens technology really shines. Considerations of shutterspeeds faster than 1/500 apply to capturing jets at high-speed passes, if relevant at all.

Equally important is using the appropriate AI Servo case of the EOS cameras supporting various tracking cases, options available with both your bodies. Also important is selecting an appropriate AF Area from the single AF point option through some of the larger Zone settings.

I shoot mostly with extenders. Here's two examples with just the 100-400 II demonstrating the ideas above. Slightly larger versions of the images are available from the host Flickr page via the URL link that is the title of each image.

Bell 412EP - Chicago Fire Department by Paul Sager, on Flickr
https://live.staticflickr.com/65535/30313877458_9a03b52778_b.jpg

Susan Dacy in "Big Red"; by Paul Sager, on Flickr
https://live.staticflickr.com/65535/30313845928_af1ed7c0d6_b.jpg

USAF Thunderbirds by Paul Sager, on Flickr
https://live.staticflickr.com/65535/29243965937_3b61cdf785_b.jpg

The OP said he wanted to mount his camera onto the WH-200. What I suggested will work fine. If he uses it with a big lens then the camera won't be mounted but instead the big lens foot will. That is a whole different issue. I just went back and re-read the OP but see no mention of using it with a big lens evn though that may be his intention - it just wasn't mentioned.
There is a bit of an issue with mounting cameras or big lens (using its foot). I have had this issue a couple of times and there are ways around it but am always surprised that nobody has made an attachment to do this - not that I have found yet anyway.
The issue is that the logical way to mount the plate to the camera is left/right but on a big lens usually front/back orientation. You can mount to the camera dual plates at right angles to each other thus giving you a front/back but I haven't yet seen anything combined that includes this plus the camera ledge that prevents twisting. If you know of one please post here.