If you have any suggestions on the best position for your head and eyes while riding I would like to hear about it, because as I tried to keep my head looking forward I found my back was telling me that it did not like this position. No sharp pain it was just muscle like holding a weight to long.
I agree that Night riding with a helmet mounted light only is the best practice to keep you focus down the trail. The added advantage of this approach is you also have to look down and around the trails on corners. So you might be looking 15 feet down the trail and way to the left (or right) of your momentary direction of travel.
Look only where you want your tires to go and only look for a moment and look for the next place in your line of travel.
Focus your helmet mounted light to point 15 to 20 feet down the trail while you are in your normal riding position. This is like pointing the light to the trail just in front of the front tire of an imaginary bike in front of you. (or you can ride behind someone and see if your light lights the ground in front of their front tire)
Important: Use your peripheral vision to watch out for low branches and other unwanted obstacles.