Speed-test figures as video-size guides

I found this speed tester:
http://www.bonvi.net/Test/index.html
in a thread from 2002. Kirupa praised it so I tried it.

I got pre-test figures like 479 and 530 and test figures like 100, 802
& 1476 and 183, 1465 & 1703.

I’ve seen a lot of these testers and I can’t figure out what the
figures mean, in terms of how “big”, i.e., total data rate (in kilobits per
sec), I would make a streaming video to ensure maximum quality that would still
download smoothly to a viewer with, say, the same particular jumble of
speed figures I got above.

My streaming server host company recommends no more than 300 kbps for my
videos, to download successfully to most broadband connections.

But let’s take my test figures above as an example.

How would I use those figures to determine if 300 really is the limit
my connection could deal with smoothly? Supposing my test figures
indicated I could handle a 450 kbps version and I could write an
actionscript to steer a viewer with a similar connection speed to a
higher quality (450 instead of 300) version of the same video. Wouldn’t
that be better than just having a one-speed-fits-all version?

If so, then how would I convert or interpret the test figures I got from
this speed test (or one like it) to make an accurate judgment on how
“large” a video file a given connection speed can run smoothly?