Hey Shazz, I find that I use a Bigsby type trem a lot more subtly than I would a normal or full floating trem. I don't think its designed for "dive bombing" and such.
I think this video is a really good example of how to use the Bigsby to its best effect. You just caress it, and it gives a beautiful "warble" to the chords. Well, that's my $0.02 worth anyway.
https://www.youtube.com/watch?v=YhGw6lgEA0s
rob