One thing you want to do also is do research on what screen resolutions your base clientele uses. One thing you want to avoid is having your users scrolling every direction under the sun.
You can use javasript to detect this and go to different pages. However, this is a lot of work and - from my experience - can fail depending on user settings, browser capabilities, etc.
What you want do is find a happy medium for page size that fits your intended clientele. This plays on what others have said here with trying different browsers, etc. Firefox has a lot of website editor tools to check out. Also, you can set up two different screens at different resolutions, two computers, or just change your resolution on desktop. However with the last one, I never find it to be the same as doing other options.