Looks a bit messy.
if i were you, i would go for a dark themed sig with that render and stock.
well as he said
its hella messy, like if its not gnna have flow at least make the messy area near the focal
the lighting is aight
if you look to the left you can see that your render is bigger then the moon lol
if you look at the left side of him and then the right, it doesnt look like the same sig