It's all personal preference really. But I'd assume most people would want to put the lights into their range finder. This would mean that you will put a battery pack in your helmet. Other people put a wireless servo that they control from their gauntlet to rotate the range finder up and down. Another pack for the helmet I believe...
Then you may want helmet fans if the lid gets hot and you find yourself on long troops. Again, personal preference but I hear these are life savers especially if you live in a warmer climate.