I know it's too late, but If you're anything like me I build a system and then justify changing it or building a better one.
Anyway once I got my hands on a battery with a bluetooth BMS I realized I wouldnt want to be without one again, sold all my prefab batteries and built new ones with BT BMS ($60 each from JBD). That way you can keep an eye on the actual coulomb counter SOC and capacity of each battery from your phone, keep an eye on each cell voltage, battery temp, adjust the balancing settings as needed/if needed and check to see if loads are balanced between batteries. Also they will have low temp cutoff and sometimes even heating option.
I assume the extra cost is probably not much different than the cost of a good shunt and with BT in each battery you get a lot more data and cell level data. Anyway if you end up building another system at some point, I can vouch for the BT being an awesome feature and hopefully that will become the standard because it wont add much cost for manufacturers so why not.