The Digital Dashboard

[Yogi]

Instead of fooling around with electric and mechanical gauges in the dashboard that are forever going bad, I would like to consider using Axiom MFD(s) for that purpose.
I have a 2000 Pro-Line 29' Walkaround with a pair of Mercruiser 5.7 litre Bravo III's. I have 2 Axiom 9's in the "glove box" area above the dash that serve my navigation and fish-finding needs. I would like to throw away all my gauges and replace them with 1 Axiom 12 in a custom built dashboard.
It seems to me I am going to need something to change the electric impulses from the various system senders to something digital that Axiom can understand. What is that piece (or pieces as the case may be) that I need?
I am assuming that if I install a 3rd Axiom MFD, I am going to have to create a SeaTalk-NG(?) network. My guess is I am going to have to daisy chain two switches to accommodate the 3 MFDs, the 2(?) engine units, VHF radio, and the RV transducer. I'll need to leave space for a radar as well.
Is there a comprehensive manual somewhere that will detail how to make such a system work?
With all of this electronic hardware in basically one space, I expect cooling will be an issue. What is the temp limit before the Axiom BIOS starts to throttle the CPUs back?
That will help me decide if I can use active air cooling or if I need to build a custom water cooling pad.