I am just the opposite from swift one.
I like the crosshair to be thicker for night hunting under artificial light. Makes it easier to find. The Firefly is a great night recticle, even without being lit up. In fact I never light mine. They are bold enough that with a red light shining on the animal, they stand out vividly and have proved effective without being lit for me and a calling partner that I hunt with. He has gone exclusively to the Firefly for night hunting. The outside portion of the Firefly is very heavy, yet the inside portion thins right down where the lines intersect. My calling partner explains that he merely brackets the animal in between the thicker crosshairs vice precision aiming.
I also use the Leupold VX-III Heavy Duplex for night hunting as well. At night the thicker the lines the better. Don't worry about how long they will stay lighted, 20 seconds of flashlight in the eyepiece is good for many hours. I can see how the lighted crosshair would be beneficial during low light, but not after dark.