I'm glad to be of help.
I'm pretty new myself, so I'd cant answer anything about the scaling of renderwindows- other than toggle fullscreen.
that said, if your screen is bigger than the render window, there is no need to render the stuff outside of it.
say your view is 600 by 400 pixels, with a center of 500 by 100 (render window coordinates)
then before rendering an object, make a test:
if(_x > view.getPosition().x - 300
&& _x < view.getPosition().x + 200
&& _y > view.getPosition().y - 300
&& _y < view.getPosition().y + 200) {
then render }
else don't!
this will save a lot of render power...
(300 and 200 should maybe be a bit bigger so things just of the edge is still rendered, also this size should be dynamic so it fits other views (300 should be view.getSize().x/2 and 200 should be the dame for .y instead
)
do i make sense or do i ramble?