HC-110 is a solvent developer, but since it's always used diluted the solvent effect is not as strong as D-76 or Xtol stock. That said, the higher the dilution, the less solvent effect you'll have. This will have no impact on shadows, but will (or might) on grain and, more importantly contrast, because it has more compensating effects at high dilutions. Ansel Adams mentions using HC-110 at high dilutions for compensating effect in
The Negative.
You won't get
lower contrast, as per your question, but the compensating effect will mean, amongst other things, that you will have better highlight details and micro contrast. But contrast will also be influenced by agitation.
I've never tried dilution F (1:79) or G (1:119), but I've read that the difference between these and the widely used B is not noticeable if working on medium or large format. Covington —
https://www.covingtoninnovations.com/hc110/ — doesn't mention any major differences, and seems to imply that you can go from one to the other, especially A or B and H, essentially for practical reasons, i.e., when development times are too short.
HC-110 doesn't increase film speed, so it won't give you better shadow detail. Good thing is that it doesn't decrease speed either. As Keith said, shadow detail will depend on good exposure.