I'm under the impression that the F20B is a destroked H22A. Same H series engine, with a shorter crank and longer rods with an F series code. That would make it an H series pattern head.

If that is true, it wouldn't work. Who's done it?

The F series is not really a series at all. The F22 is the basic F, the F20B is a converted H-series, and the F20C is similar to a K-series.

Oh, and I did leave out the D-series DOHC hybrid. A shop actually did fit a ZC pattern DOHC head to an EW (early D-series, aka D15A3) block. It used a weird timing belt though.