Wiring in parallel - both leads from same battery or from different ones?

[NPCampbell]

This is my wild a** guess on why I'd always pick the first picture ...

In the 2nd picture, the battery closest to the load should always wear faster (by maybe 1-2% with heavy loads?).

In the 2nd picture, the battery closest to the load will always provide more current until the:
(internal resistance of the battery closest to the load) >=
(the internal resistance of the farthest battery
+ resistance of the jumper cable)

The internal resistance of LA batteries increases proportionally as the voltage drops so the farther battery will catch up quickly as the front battery discharges.

However, with lithium batteries, the problem is worse because the voltage doesn't drop as much as LA during discharge, meaning the internal resistance won't vary much either. 2x3 feet of 4/0 copper cable is .3 milliohms and the internal resistance of a lithium battery may not increase by that much over 30-40% SOC. Therefore, the farther battery may never carry as much current as the nearer battery for the entire life of the battery.