Where you buy (the amount of profit you are sitting on) has nothing to do with where you sell.
You set a stop and move it up when the share price moves up. When it is hit you sell regardless of profit or loss. If you are not working with a stop in spec shares you are risking your entire capital rather than just a percentage of it.
You can ALWAYS get back into a share if you sell. Your system should be more important than profit or loss on any particular trade.
Sorry for the tirade but I know so many people who have lost so much despite all the books out there tellling one have to trade safely.
SDL Price at posting:
0.0¢ Sentiment: Buy Disclosure: Not Held