I'm not sure at the moment if the ratio is a buy signal. A high B:S ratio would give you quite a bit of insurance about it falling back to a ratio of 1.
It may not lead to any greater percentage change than a share with a ratio just above 1.
It would just need a huge amount of sellers to push it down to the 1 level.
It would be nice to see about getting the Market Depth.
Turbotrader does it.