I appreciate all of the info everyone provided. I sent a question to Cummins but they never responded.
The point of 350A for less than .5 seconds and then dropping to 75A provided by MikeH is very helpful.
Somewhere in internet land I saw where someone measured 280A on a 4KW unit.
This maps with folks stated experience of successful starts with various lithium banks:
2 Battle Born 100AHr: max discharge spec: 200A for 30sec. = 200*2= 400A for 30 sec.
2 SOK 206AHr: max discharge spec: 200A for 3 sec = 200*2= 400A for 3 sec.
2 SFK 300 AHr: max discharge spec: 200A for 2 min. = 200*2=400A for 2 min.
I haven’t seen any reports of a single one of these batteries starting a generator
The AMsolar webpage states that a single LifeBlue battery can start an RV generator.
LifeBlue 100AHr max discharge spec: 350A for 3 sec (> 400A for 4 sec will trigger an over current event)
This provides me with some options within the limits of the battery area and wanting both the heated batteries and Bluetooth.
Thanks again!

…Mike