Best Practices – Selling to protect profit$

Hi Pat - Good morning! I understand the concept of selling some shares into strength, and that makes a lot of sense. With regards to selling some shares on weakness, I understand that the 8 day EMA is our first line of defense, and the 21 day SMA is our second. With regard to intraday activity, do you wait for a close below the 8 day EMA / 21 day SMA before selling some shares, or sell some when these lines are crossed intraday? Does the 1st 30-45 minutes of the day, with it's natural volatility, affect your decision for the above? Will an intraday cross below the 50 day EMA intraday prompt you to close the position entirely, or do you sell some more, then wait for a close below the 50 day SMA to close out the position? Anything else I am missing? Thanks
Mike