In answer to the above question - I believe it took me about 3-5 minutes to put them on the first time. I've moved them once to another helmet and it was under 2 minutes to move them. Luckily I have 2 helmets, so that I can have one that I use with the kids and one I use for commuting so I don't have to take them on and off, which would be a pain.

As for positioning, I did play a little with the positioning the first couple of rides until I found the 'just right' spot and I haven't moved it since (that was over 2 years ago and I ride nearly every day). I have gone through 2 pairs of headphones in that time though =).