Manage premature entry fail and max distance of the initial buy from pivot

Hi Patrick, Amazing work you guys do on this site. I have 2 questions:

• Today (07/05) I've bought CPE at 41,50 on good volume looking the 30-min chart. But It fail on the next bar. I've sold all inmediately with a little loss. It was a reasonable entry or I should have avoided ? Have a I sold correctly?
• Which is the maximum recommended distance allowed to make the first buy from the pivot? 3%? 5%?

Thanks,