Im only a noob to shaders myself, so I havent tried decoding your code,
it is more complex than I have gotten yet...

But on the off-chance it helps you, I recently discovered,
the hard way, that IF a texture you are reading from is not 'square',
then the individual pixels themselves are not square either...

So maybe the width and height distortions you are getting is due to your
entSkin1 not being square...

I hope this helps you out some...