Hard rock:
CTRL+A -> CTRL+J -> Open difficulty settings, increase circle size by 1, set AR to 10, OD to 9~10 (usually 10), Drain to 8~10 (depends on the original drain) -> Save as new difficulty -> XXX HR -> enjoy.
I'm doing it when I mod maps which have objects in questionable places (usually HP Bar).
Obviously difficulty settings should be approximate to the diff+40%, I just took an example of an average insane diff up there. Easier diffs don't really require much attention, except for the inverted part.
As for double time, well to be honest while I do agree it would be a nice thing to have, it certainly isn't really required. Nomod ranking is the norm, but I do agree that objects shouldn't be offscreen or stacked wrongly because of hard rock.