Selling Rules according to Moving Averages

Hi Pat,
I am recent member of this community, which I find awesome. 
Some doubts about selling or decreasing positions have raised lately, especially with swing trades, and I would like to ask for a scheme to manage selling rules according to daily EMAs (8, 20), and how they are related to the share of the position to be reduced.
Also for instance, how to manage them, providing only 2%-3% gain was obtained after the break-out.  
 
Best regards and thanks for all the insights you are sharing, they are really mindblowing.