I am unaware of that being an option. I assume you are talking about how much of your profit you decide to green up?
This has been covered before, on Peter's Blog I believe?? In the long run you will find the profit is fairly similar irrespective of greening up or letting the profit run. If we assume the market is efficient then given a large enough sample the P&L result should be the same.
I also found in the early days of my trading that the stress of a higher win followed by a lower one was not good so I went for the slow and sure approach and greened up or redded up (is redded a word

) and that removed a lot of the emotion. If you get too emotional about trading it can have an impact on your decision making and trust me it will not be a positive impact!
HTH
JG