Your initial thought in your first post on equalizing current calculation is generally right. We just add some points. You now also correctly concentrate on max charging current, because is lower than discharging.
DCIR depends on aging of the cells. Fresh new Sanyo GA is about 34 miliohm at 3,74 V and 25 °C.
First let calculate the internal resistance of the cells only for one battery :
(34/10) x 14 = 47,6 miliohm. For two 14s10p packs is total internal resistance 47,6 x 2 = 95,2 miliohm. We can round this number to 100 miliohm = 0,1 ohm to simplify it. Moreover fully charged cell has DCIR little bit higher.
We don´t want exceed max charging current 0,3 C = 1,1 A for GA cells. Such capacity as 10p battery can probably keep significant equalizing current in order of minutes or more.
If we consider 1,1 A per cell which is 11 A per battery, than we get total voltage drop 11 x 0,1 = 1,1 V.
It is theoretical voltage drop on the cells only.
Now we have to add resistance of other parts like wires, transient resistance of the connectors, nickel, spot welding resistance, BMS, … For simplification let consider 100 miliohm, it is another 1,1 V drop.
Resulting safe voltage difference for this simplified example is 2,2 V.