Video Quality

I've been playing with the various upload settings.
I've uploaded a 45mb mov file at resolution 1440x900.

I used the default transcoding settings for the upload and put the movie into my wordpress post using the all in one video plugin.
I set the video width at 520px using a custom video player skin.

In the transcoder settings it says the video will be played to optimize the viewers broadband speed and screen settings, but when the video plays back in my screen it is at a much lower resolution. Almost un-viewable.

Then I uploaded the video using the source transcoding setting only.
Plugged that video into my post when it was ready.
The video looked great, and played at perfect resolution.
Only problem this time, is it took forever to buffer. Over a minute.

My question is this:
Is the buffer time directly proportional to the filesize and transcoding setting?
I'm trying to figure out the best combination of buffer time and screen setting.
Since my videos are audio over powerpoint presentations, I need to have good resolution so the viewer can read the slides.

Any ideas on how best to accomplish a resolution of at least 1080 without having to wait a minute or longer for buffering?

Thanks.

Craig

www.hardmoneyu.com