I use a Ram Mount, built in the USA (so very difficult to get parts here in CH without paying stupid shipping fees), but it works a treat.
It's mounted on the steering damper using the supplied curves bolt which matches exactly (by chance) the diameter of the damper
It holds well, and is not so tight as to damage the damper. The guys at the shop liked it a lot.
I also have a cheap (but waterproof) USB port that I found on eBay. About 5$.
The advantage is that it's positionable, and allows use as a gps / dash cam or for taking time lapse video of rides too
For Harry's lap timer, I block the camera on the iPhone to record black video and then use a gopro to record nice footage. Then you can overlay the black using chromakey in a video editor to get all the details, such as corner names etc, but on the nice video feed.
Don't get an odb2 reader for Harry's lap timer as the duc doesn't support the protocol fully (it's blocked on purpose) and you don't get rpm or speed details as expected. I think it may be possible if you flash the ecu, but I haven't tried that yet as I'm a bit too scared to do so at the moment.