The booster wont force power into the system, The system will only draw what it needs. This should work fine.
I will probably go ahead and upgrade my battery this winter, but it’s been fine so far. Not looking at a dual battery setup as I just don’t have the need with the few accessories I run. I see what you’re saying though as a backup, I just don’t want to invest that money. This should serve a few purposes like charging the phone, tablet etc.Get a dual Battery setup with a VSR to to isolate the auxiliary from the main battery that way the starter will have enough to start and run the maverick
As for one of the boosters/jump starters your looking at they have some applications after all they show the thing starting a (diesel truck ) hooked up to a dead battery will just bring the voltage down on both
However those can keep your phone powered if you break down for real for days