I read a nice essay by a hedge fund manager once, alas I forget who--Mr Dalio maybe?--that set forth a nice step in the middle ground between value investing and mechanical.

They analyzed a lot of well known investments, including all of theirs and several by other folks, and did post mortems. They asked two questions of each. What was the key cause of the failure of the investment thesis? and What question, had it been asked in advance, would have made that problem foreseeable?

Then they built a really big checklist from the answers to the second question. For any new investment idea, they run down the checklist, and if it fails any of them, they don't invest in that idea.

This approach could be a big help in keeping one's watchlist down to a manageable size.

Jim