IIRC, you can indeed combine B mode with ePedal, for maximum regen. Keep in mind, though, that regeneration is less efficient than coasting, whether in Neutral or just by using D mode and lightly pressing the accelerator pedal to eliminate the normal bit of regen that simulates an ICE with automatic transmission. Which mode is most efficient depends on the driving situation. In stop & go or stop & slow driving, ePedal or B mode (or both at once) are best. On the highway, Eco or D mode are best. D coasts better, but Eco limits the power draw from the HVAC system, and makes it easier to accelerate gently.