No need to flash the nosewheel light, just use the ground crew call button, trouble is one may be interrupting an in depth discussion amongst the ground crew about over time, meal breaks, or a dozen other subjects.
Have used hand signals from the FD of a B744 but headsets are a lot easier.
The mantra recited by the ground crew was instigated by pilots to get those checks on the CVR in case there is an incident during push etc.