I don't see why you would use mr11's. Apparently mr16s put out a lot more light.

I have JUST started using Halogen lights for night riding. I am using OSRAM's IRC lights, which put out a lot of light for their wattage. They claim 35w halogen light out put from a 20w light. I use their 20w Flood light. Its really good for forest riding, but i really want a 10w spot+10w flood. But they don't make IRCs with such low wattage (or at least i don't think so).

With a 12v 20w bulb and a 3.4Ah 14,4v pack i get 40min bright light and then 20min of dimming light. I need more run time.