Note for charging.
if you take 8, 100AH cells put them in parallel, they will still only allow for a 0.5C Charge rate of 50A max. It is NOT additive.
??
8, 100 Ah cells in parallel is 800 Ah. 0.5C charge rate would be 400A.
However, you can't be sure current will divide into them equally. If 7 were at 0.75 SoC and 1 was at 0.50C, as they charged into the knee of the curve, seven would slow down their charging waiting for the one to catch up, so one cell would get most of the current.
Seems to me for top balancing, best to limit charge current to what one cell can tolerate.
For operation in a pack having multiple cells series/parallel, charge and discharge currents can be higher than for a single cell, but not as high as the number in parallel indicates, since there will be some current imbalance; allow some margin.
Parallel balancing 2240 Ah of cells, you're not likely to charge at 0.1C, wouldn't have a big enough supply. Whatever constant current rate it can deliver, I think 1% of initial current would be good enough to call the cells balanced. If you had a 40A charger (5A per cell), then 400 mA (50 mA per cell) might be a good ending point.
Be aware that charging to 3.65V at 50 mA is higher SoC than 3.65V at 500 mA. If charger output is very low or total cells Ah capacity very large, could use a lower end voltage to avoid driving to higher SoC.
Steve - you said 0.05C was recommended - is that recommended endpoint for top balancing? Or just for termination of charging once assembled in a pack?