Yeah you need to excecute what's called a "trailing limit" where a stock robot does the bidding for you by watching constantly as a stop dives down to rock bottom and then on the earliest upswing it picks up your stock.
No, the issue here is how good the broker is at finding the best price.
I like to use limit orders for buying and selling. I think that on the average you get better results with limit orders.
Check the bollinger bands. They will give you the upper and lower bands for the stock. Check both one day and 3 month charts. Use yahoo finance, technical indicators, bollinger bands.