I went to a busy fly-in at the weekend. As I turned base, an aircraft on final called G-.... Final, contact one on. As I turned final behind him I called G-...., Final, contact one on, one ahead. Letting the guy in front of me know that I was aware of him as well as the aircraft that had touched down. There's nothing ambiguous about it. It's good airmanship, has worked well for many years and is certainly standard procedure when A/g or safetycom is in use. I don't think it matters much whether you say Contact or Visual. You'll still be understood.
Very often an air/ground operator will only give you airfield information and it's up to the pilots to sort themselves out. That's where the value of such calls lies. Anyone who's confused by them needs help.