The literature that comes with HCD gives a development time of 3 mins (as always) in HCD-S and 24 mins in HCD-2.
Results? Not very good, the negatives are very thin and underexposed. I'm not sure if my meter works well at this high EI value. Maybe not.
These two are the only ones I could scan, and even then, they have quite a lot of work in Photoshop.
This one is a banana, in case you are wondering. If my meter does not work well at these speeds, I'm not sure I can get the advantage of pushing the films, although the results are not as grainy as you might imagine.