Not a bad sig. The render can ultimately be any size it's the artists opinion on how big or small it should be. IMO it's a tad too big but keep it how you like it.
I guess i only have one real thing i would change and that would be teh text. It stands out a lot. I would try blending it more or moving it away from that black on the right there. I'm liking the bledning on this one as well. The lighting could probably be a little brighter on the left side but it's not too bad. Keep at it.