I do know Sorenson a bit, but dont have time to experiment with settings.
Nobody here can give you any magic setting or settings. At least spend a little bit of time experimenting with some of the presets to get a better understanding of what's going on, what output format is going to be the best for you etc.
A similar question to yours would be something along the lines of:
"I've got a car, how do drive it? I guess you need to know my engine size? I'm dealing with a garage but they don't even know what petrol is. I know how to drive a bit but I don't have time to learn all the controls"
When you say universally playable - do you mean playable by the largest possible audience?
If so, go with Flash, as it exists on a bout 98% of computers.
I would suggest taking the video into your video editor and re-exporting at 640x480 or some other square pixel based resolution (such as 320x240). the current resolution is designed for broadcast - over the web (as on your PC right now) it will appear stretched. Your compression program can change the aspect ratio, but it won't look as good as if you did it in your video editor.
As far as settings go, your server speed is not really the main issue - you can have a great speed, but if my connection is slow, it will DL slow. The goal is to keep the file size as small as possible while keeping the quality up. Period.
Take a look at the different presets and give a few of them a go. Compression is a lot of give and take, and once you understand what the different compression properties do, you'll have a much better ability to make the right decisions.