Need advice about nail clipping

my rabbit has very dark nails. They are so dark that I can't see the nerves in the nail. This gets me very worried about cutting his nails as I have absolutely no compass to determine where to stop....I am literally testing my luck 🙁   I took him for nail clippings on numerous occasions, but really hate doing so as he is VERY nervous. Does anyone have any tips for this ? how can i determine where his nerves end if I can't see them ?