Can you share a link to the video you're referring to? Curious to see it myself.
I received the MasterVolt charger and installed it. I found their documentation extremely lacking (sounds like you did as well). Some of the functionality is hidden. To unlock the advanced capabilities...
Planning on moving forward with the ChargeMaster Pro 12/75-3. DC1 and DC2 share a charging profile (in my case I'll only be using DC1, with LiFePO4 profile). DC3 can be constant voltage of 13.25 and 10A. DC3, when receiving a charge from the alternator, will charge DC1 with the LiFePO4...
How to charge LiFePO4 and Lead Acid from both shore power connection and alternator comes up frequently. I'm finding myself in the same boat.
Initially I had decided to get a DC-DC charger (Renogy) and stick with my shore power battery charger (which does not support lithium) for the time...