Get a magnetic rechargeable led light you can stick to the housing above where you need the light. Many are adjustable so you can aim them exactly where they are needed. So you are in better shape for next time (there will always be a next time) because it isn't much help now. Once you succeed in getting the sheared piece out and the new bolt in. Mark the shaft and the hub clearly on both sides either with a paint pen or something that will be relatively easy to see with a flashlight or whatever you use next time. Of course with good light the sheared bolt will be shiny when you look in the hole if you are able to. That depends upon how much room there is.
If I followed the idea that someone put forth to put a second hole for alignment. If you put it further out away from the actual shear pin hole and only go maybe 3/8" deep it won't weaken the shaft and it will give you a positive alignment method that could save you much aggravation. Whomever suggested it had a good idea. As long as there is room to stay clear of the shear bolt hole it would have no impact on the function or strength of the shaft.
