I suppose it will all come together when and if I get to do any full downs. Practice ones, that is! I just started scratching the surface of commercial training and my commercial instructor is already having me do some full down precursor exercises, settling into run-on landings, so maybe towards the end, although my understanding is that commercial students don't do them either.
Strange,
during my JAR-FCL PPL-H (in Germany) I did many full downs.
Same during my practical exam, and each and every yearly type rating refresh ever since. Small difference: Some TREs set the engine completely to idle, some held it up at about 2.000rpm ("just in case").
And back to topic: If I remember correctly (now i initially start really thinking about the details of the flare), I also give it a little collective. But I'm not sure. I surely will discuss it with my piloting friends.
Best regards
Spartacus