Hi Neil,
<<One thing that may be useful when considering successive buys at lower prices is to look at the price/book ratio.
If the ratio is getting lower you are at least safer as the price approaches the book value.<<
That's a good point about looking at fundamentals, but you really need to do this before you start AIMing a stock. Once the stock drops by a big time you have a big decision tree. Do you continue with AIM hoping the stock will recover, do you just stop and wait, or do you sell out at a loss.
Also, looking a the price/book value may exclude many strong companies. For example AMZN has a ratio of 44, so how do you use this?
Adam