Thanks for the advice y'all... As mentioned I used a dewalt multi-tool. Amazing tool. I bagged off the inside with duct tape and a kitchen trash bag. Worked GREAT! Thanks for those tips. I don't have any work in progress pictures, I should have taken some. Anyway, after careful alignment of the provided template I was able to make some cuts. The width of the existing cuts was a little larger than the simrad but I was able to make do. You can see on the left hand side there are some marks as to where the radio used to be. Anyway, I think it looks great and I don't need any extra starboard.
I also installed a Halo 24 radar to replace the early 2000s raymarine unit. Very easy, bolted right into the original raymarine mount! This new radar is very nice compared to old one. You can clearly see the dock fingers on the screen, very impressive! I haven't taken her out yet, very excited.
I networked the nss12 evo3 to the lowrance HDS7 using a simple ethernet cable and NMEA2000. Can share sonar, radar, waypoints, etc.
Fingers crossed, this was much easier than I thought it was going to be. I still should re-org the wiring in the dashboard but I will save that for another day. Sure was nice to rip out the old electronics.