Hi Harry,
Can you write-up a couple of sentences describing how you create your video tutorials (software used, screen size selected, etc.). Not wishing to 'steal your thunder', but I am sure others (like me) might have some simple hints that are easier expressed in 30s of video than 30 lines of forum text !!
FYI, I have Camtasia Studio and would be screen-capturing using that, before post-processing to minimise file size.
Cheers,