I have two questions about the series 3 watch. 1) Can I buy the GPS + cellular version and not activate the cellular part immediately? I'd actually like to start using the series 3 watch but won't really need the cellular functionality (and added 10 dollar a month payment) until December or the beginning of 2018. If I have to pay the $10/mo starting now, I'd probably just hold off and get the watch in a few months. 2) Is there any advantage to the smaller 38 compared to the larger 42 other than personal preference? It seems like the 42 is a more powerful device, no?