Just punch out the small cap in the center of the lens cover and that will give you a good view with your IR light at night. Completely open will not be focused properly or clear as DoubleUp mentioned.
As to lights, I too have more than I need, but currently I am really liking the TR-38 light (not T-38) that I got from the UK, and I am using a 940nm pill in it. It's good for at least 100 yards in the woods. Before that I was using a T-20 with 850nm.
The Photon is so light-sensitive that a GOOD 940nm light will work very well. I ordered one from China for $28 just to try that isn't good for much unless you like paper weights. The TR series lights are good.