All of my EA's are single entry and exit, I only let each EA open one position each at any given time, It's just the easiest way for me to code at the moment, untill I get a very thorough understanding of the MQL5 language. I usually spend my alot of my days at work thinking about different ideas, and writing them down. Then when I get home i sit down and code for hours and alot of the time it leads no where. Can be very draining but it's worth it when you come across a concept that has a positive outcome.
I have a few new models that are still in optimisation, Showing some good potential. Will post some back tests early this week.