I'm with JMC here. I must have a slightly larger Lance batt box than he does as a grp. 27 fits in with enough head room to pull cables off the terminals.
After recently upgrading to a new PD converter and adding 200W solar I replaced my 6 yr. old, grp. 27 Kirkland batt from Costco with a group 27 from Costco now called Interstate. The clerk told me the Kirkland brand was always an Interstate just rebadged.
I use the same size 3 batteries for the TC; two under the hood of the truck and one in the TC. They're all hooked together with a heavy cable. I do have a knife switch cutoff which I've never used in the open position. Now if i could only keep the fridge going on propane on the highway I would and eschew the 12v. running while on the highway. Only once when I left the 12v. on by mistake all night did I take all 3 batteries down enough that the truck would not start in the AM.
It looks like not in my lifetime will I get to enjoy the rush of having 2-6v. batts to brightly and warmly wile away the evenings in winter.
jefe