I think it all depends on the opponent. I tend to go with the narrow diamond because it's so effective:
But any form of the 4-5-1 meets the criteria I look for (each striker double marked, any attacking midfielders marked, equal or more number of midfielders). It just has to be tailored to exploit weaker players of the defense (e.g. If they have weaker defensive wingers, focus passing on the wings). There are also many variations of the 4-5-1. Here's how I think they should be used:
If you need to be super defensive against a much stronger opponent:
Fairly equal opponent:
or
You can even go crazy if it's a weaker or much weaker opponent:
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Honestly, looking at the above, of the 4-5-1 formations, the V looks very balanced. It gives up a little on the wings but if you have good DL/R, it should be ok. 4-5-1 flat looks good and 4-3-2W-1 looks even better.