I also ride quite a bit at night and use a little over 1000 lumens and this works great for me at speed.. 350 lumens is for most but there are plenty of new lights built with x-ml leds that put out close to 1000 lumens on high.

You know you have enough light when you roll up behind a car and they shield there eyes and you see them mouth to themselves "art bell was right the grays have finally come for me"