2019 Bay Star 3401 battery bay/tray dimensions?

[Allentc2]

I had a solar panel system all worked out with an installer, but now I'm wondering if I should spend the extra coin on lithium.

Right now the system feeds 6 300aH 6v AGMs...which aren't small OR lightweight. What I'm considering are 2 300aH 12v Lifeblue lithiums.

1) Will they fit? What are the measurements of the 3401 battery compartment or whatever? I am gonna have the residential fridge, so there should be 4 house batteries total. How much room do I have to play with?

2) Is the battery bay closed? I'm told lithium doesn't like the cold (much like me) so they'll only put them in a 'closed' bay.

I've called Newmar, just hoping for a quicker response time. LOL Thanks in advance!