About the tail varying in size: it doesn't vary...well, vertically at least. I lined up everything so that it would be easier to draw later. Probably not the best way, but it did ease the process.
I also didn't use a spray brush. I'm just not very good. My color choices probably don't help anything, but I tried balancing strategic and random placing to create a fur texture. That, obviously, didn't work out.
And about the noise; it doesn't bother me, but I have had a quite a few (like 50%) comments about my stuff being too noisy. So, again, probably something I should work on.

Thanks for the comment =D

I'm impressed with the the 3D, although the hail seems to vary in size.

I do think that this pic is far too busy however. Too much noise, what with the background, the fur and even the frame. The fur looks like you've just randomly placed pixels to create a texture, maybe using the spray brush. That never looks good. In my opinion, it would be much better with a more defined texture and a simple background, or even transparent background.