i60 wind instrument: standalone installation

[Teranodon]

I am about to install an i60 wind instrument in standalone mode. I actually do have Seatalkng on the boat (it runs the EV-100 autopilot) but I don't see any advantage to using it, and I would need a long, expensive spur cable. So I have two questions:

1. In order to provide DC power, do I have to set up a bare-bones Seatalkng network (e.g., two T-pieces, a backbone cable, a power cable and terminators) or can I simply butcher the provided short spur cable (in which pins 1 and 2 appear to carry power/ground)?

2. Am I allowed to split the long data cable at the base of the mast, using the provided junction box? The instructions very explicitly say that the cable should not be split.