[Putershark]

Not hard and it is up to you if you want it to be in-line with the keel or for many are not.

You do need to be careful about the placement of the compass around a lot of metal objects as you well know, but the VHF may or may not cause a problem? What I would do is have somebody hold the unit where you want to mount it, and then "key up" the microphone on the VHF and "see" if the compass moves? That would be one thing (since it is not constant) that you could NOT adjust out using the compass key

Hope this helps some?