You can put it anywhere as long as it can communicate via bluetooth to the troller. Be sure there is no magnetic field around it. Of course you need to access power to it. Use two sided tape to temporarily test it in a position if you like.
Most people put it up at the bow somewhere, on the deck, or, under the mount arm when it is stowed. John Jones likes the position under the mount arm.
Like you, I did not want to drill any more holes. I never use the cup holder up front on my P2, so I used it. There is already a hole in the bottom of the cup to run the power wire up to the bow. I used 3M two sided tape to mount a piece of plastic to the rim of the cupholder, and then screwed the sensor into the plastic. No holes drilled at all and it doesn’t move.
The sensor is supposed to enhance spot lok. I found no difference, with, or without. You do need the sensor if you intend to use the jog function. I may
not even install it on my next boat because I don’t use the jog function.
