Preview - remember window sizes

I find it extremely irritating to keep having to resize every Preview window that I open. I'd rather it always remained a specific size. I've been searching for a while for a solution, but seems no one has found one yet.

I use Preview a lot for viewing photos and PDF's. Others suggest using Adobe's PDF viewer, but I like Preview because it is very light and responsive.

Anyone come close to a solution for getting Preview to remain a constant window size?

 

Cheers - I downloaded Skim and I've now made that my number 1 for PDF's! It's pretty cool. And it remembers window sizes!

Only glitch I'm having is that when I want to zoom in, I have to press:
CMD SHIFT + as opposed to CMD + because by default on laptop keyboards the += button = is the primary key.

Is there any way to reverse that in this program so I can zoom in without having to press the shift key?