Late but completed a dual battery install a while back. I used the M.O.R.E. Offroad tray built my own hold down, I uses dual 500amp relays to isolate the system one for single/parallel batteries, and one to kill power to the winch for the day to day when it does not need power.
This was while in progress was about 90 percent complete
Built a windshield bracket for dual lights. I think it came out nice, I just have to re cut the angle for the light tabs get them facing out and not up.
Also while not so much the Jeep it is for the Jeep, I am building and Expo trailer for those long trips up in the mountains. Parts are trickling in, waiting on my wheel adapters, wheel and tires. Also waiting on my new welder picked up a Millermatic 211.