Since I'm not running solar yet I went with this to isolate the batteries. I also went with the NH Overland battery tray like the other poster did.
I've been trying to find info on if it's OK to run an AGM deep cycle battery with the OEM battery in this configuration, but haven't found anything yet. From my limited understanding so far, the AGM will not get a full charge from the alternator if used with the OEM battery as primary. I may just run an AGM charger in the garage to top it off the last 20% or so. Or just go full yellow top for the starter and the auxiliary which I believe would then allow a full charge from the alternator??
I believe his Redarc solves this issue.