Hello, and welcome to the Forum!
I think you are doing a pretty good job and you realize what you are doing.
However, the min count of trades are small, you need to keep at least 300 as a min.
If you tried and you fail to get any strategies it is because you have a small number of bars?
If you use the Free Forex Historical Data app, there are more bars, why would you use less than 15k?
Also, you may want to try generating EAs not just for the GBPUSD because this will bring you more diversification.
Cheers,