The early 20H's are an odd one. They are 93-96 generation, so are actually same generation as the V1/2 EJ20G's, but i'm sure they must be different, just no idea how different, or what's different. But for example, they have a V3/4 style intercooler and intake manifold, and under manifold turbo intake etc, despite being made from 93 on. So i think there's a mix'n'match of new and old tech in them. If i had to guess, i'd say they are actually closer to the V3/4 20G's, but that is just a guess.
In short, they are weird, and no i don't know what HG you need to use.