[CA] Adding STNG and N2K to exisiting Seatalk

[Grantj]

I need help to properly integrate an existing 2004 SeaTalk installation with the addition of new equipment. The current setup has (2) C-120 Classic MFD's connected to a RS120 GPS thru a D244 junction block. In addition, there are (2) ST60 depth instruments daisy-chained together, with one of them powered from a 12V buss. The C-120's and the ST60's are not connected to each other. I would like to connect those 5 devices together on a single SeaTalk network. In addition, I want to add the following:

EV-150 A/Pilot pack
NMEA 2000 AIS device
STNG network as required
NMEA2000 backbone for future expansion
Actisense NGT-1 NMEA2000 to USB gateway for PC access.

I believe I have the network connections figured out, using the SeaTalk to SeatalkNG convertor and various cables, etc. I need to confirm the correct way to power the SeaTalk bus in this configuration. Right now, the ST-60's are powered from a 12V source to one instrument, and the C-120(s) appear to be the power source for the RS120. I know the RS120 has to stay on the SeaTalk network to function. What would be the best way to supply power to this setup?
(2) PDF diagrams attached, any help much appreciated!