anyone doing it?
can you connect it directly to the canon, avoid the need to sync in post?

I do that with my 5D, using a special cable, as, although some people say the sound is way better taken by the Zoom than zoom>canon, I hardly hear any difference

You can take the output from the headphone/line jack but there are considerations. Among them, the distance between H4N and camera -- on a long run the signal can be subject to noise and the quality of the amp used in the H4N. Test it before depending on this method.

Have you thought about something like a Juicedlink ? Beautifull sound, and no problems with sync. Simply plug in your shotgun and/or your radio mic. Full control over audio levels, with amazingly clear sound.