Jeff,
Fire away! The weight isn't enough to make a difference.

I make my own lighted nocks. One thing I do different though is I don't set them up to turn on when the arrow is released. I sand the nock just enough that I can pull it out by hand but it's still snug when it's in the arrow. Then I just turn it on when I get in the stand. The lights last a long time. I can get thru a season doing this. I have had to many not come on before when they were shot. So I fixed that problem.

MC