Its the same size as all my sigs 480x180 i use this size cuz then i can add more detail in unlike the tiny sig sizes like 100x20 then like you only have space for a render and a gradient background. I didn't bother to add any depth cuz i cba messing around with it any more than i already had the focal was a mistake lol i kinda went overboard with the amount of effects i had put into it :p
and yeah reyjr i only used the preview of the c4d i cba to download it and stuff lol
Try using something like 450x140, I would either go smaller or a lot bigger. It is around what everybody else uses because smaller looks better
Don't worry your still not bad, just go smaller

Another thing this may not look as bad to you is because you are using an HD monitor, with a smaller resolution. I noticed when I went on my old computer to look at some of my sigs that they looked bigger and less defined
And not to overcram, but you should try a new style as well

I would be interested to see the result