You’ll usually want select the heading sensor as the Evo3 internal gps will only give you heading based upon movement as they don’t have a default orientation whereas the Point-1/Precision-9 are orientation dependent. The Point-1 can be selected as the position source for the Evo3 via the network/sources menu as long as they are both on the same NMEA network. You also can’t use the Evo3 internal GPS for the NAC1 as there is very limited setting adjustment to that model of autopilot computer; it’s meant to be more of a plug and play installation.
I’d definitely recommend installing the Point-1 on the hardtop or somewhere else that is less likely to be subject to stray magnetic fields (thanks, seasick). You can zip tie the cable to the hardtop frame tubes and run through a clamshell/hole, outboard of the stbd switch panel, to the electronics box or cabin (wherever your you decide to install your NAC1.
Let me know if you have any more questions. I spent a lot of time on the phone with tech support learning how to get the firmware updated so I’m somewhat familiar with the installation.