Don't know that there's a universal answer. Distance from fly to indicator is entirely dependent on the water you are fishing (depth and speed in particular) and the size/weight of the nymphs (and weight/shot) you are dredging. The nymph needs to be bouncing, not dragging, the bottom (thus the old saw if you're not hanging up occasionally, you're not getting deep enough
) with the indicator staying within reasonable and visible contact.
Seven-to-eight feet seems like a LOT, though.
Having said that, I should add that I hate