Actually I just figured it out.
I'm importing the FLV into my movie and the wizard that comes up sets up a componant to load and play the video.
Here is what I had to do. First, because the FLV is separate from the .swf, I was not able to use the typical preload method of comparing total file size to the amount downloaded. Instead I created a preload animation that is 100 frames long.
Then I imported my movie from frame 1 and changed the autoPlay parameter for the movie to false.
On frame 101 I have my only bit of actionscript:
where the Instance Name of my FLV is introMovie.
So on frame 1 my movie begins to load and doesn't play until frame 101, so depending on my setting for frames per second I can vary the time that I give my FLV to download before playing.
Note that this will allow you to increase the bufferTime parameter for your FLV while still showing your visitor something animated.
Also, because I have a large FLV file I am not actually loading the entire thing, but just giving myself a large enough buffer so that the video can run smoothly from start to finish.