Okay, this is what I can tell you, and it isn't much.

There's a trade off between Total Bandwidth and buffering. The higher the bandwith, the better the quality, but more chance of buffering. Tests I've run led me to 640 Kbps to avoid buffering, and I have DSL with 1 Mbps, that's been tested and shows better than 1 Mbps download rate. A total bandwidth of 770 kbps resulted in buffering too.

THere's a trade off between smoothing and resolution (size). The bigger the size, the more smoothing you need. The test I mention above was rendered at 420x315, with best smoothing result set at 78 for this WMV.

I've abandoned the idea of having a private stream. The reason is that alternative showcases (blogs) are full of kids. I can't stand kids anymore. I'm 57 years old, and getting crankier all the time. So now I've settled on Vimeo. They have a mature clientele, and there's great community features. But, now I gotta render it at 512x384. So, now I'm running tests again to get

1. Bandwidth that doesn't cause buffering
2. Size with good quality vs the smoothing required (more is required, due to larger size).

I've spent the majority of today trying to get what I want outta Vimeo! Another day, shot to hell.

Maybe my life would be easier if I had a better renderer. I'd love to have Adobe's suite! I'm spending way too much time trying to get the sweet spot. Way too much, and I'm starting to go nuts!

If I were you, I would not be concerned about file size. Your stream buffers a little (and I've seen worse buffering from Vimeo users). I'd lower the total bandwidth if I were you. Just a tad. I'd also do one other thing. Add effect -- Bump up your saturation just a little, perhaps 6 pts. Your butterflies will rock. It's already great. It would be just a little bit greater.