I run a Castle MMM and use 3.4v/cell as a cutoff - this is for a Sav Flux, have another in a FLM Ext EMaxx set at the same value and a 3rd in a G2R set at the same lvc.
I run 5000mah 2S lipos x2 and with this cutoff, I typically see 3700-3900mah going back into the lipos on recharge staying comfortabley below the 80% guideline.
These heavier MTs need a higher lvc - that way they don't overdischarge lipos.