There have been several osses over the years - there was a white one called the Peace Oss, when the soldiers got back from WW1 and there are photos of it somewhere but I think it only lasted the one Mayday. I imagine by the end of the day the white 'skirt' would have been filthy, having been swung around and dragged in the dirt all day.
But there are children's osses too, as well as the two main ones.
When I was there in 1972 the scouts had their own one and there was another even smaller one, about the size for 8-9year-olds.
The Red Oss is also called the Old Oss and is supposed to be the original faction. The Blue Oss was the Temperence Oss (Blue ribbon) but today there's just as much alcohol involved in both sides.
The Halanto has been covered on other threads here and there has been much debate on the meaning of the word. Nobody really knows for sure - maybe there were Cornish settlers who took the song to America in the early days - it's possible, but my experience has been that the early settlers in NZ just left all that stuff behind in the 'old country' and knowledge of it had died out within a generation. My grandmother was a first generation kiwi and she knew nothing about Padstow or Mayday, even tho' her sister, born on Mayday, was named May, and her grandmother, who ended her days living in the same house, was actually born in Padstow. My grandmother was almost 80 when I told her about it.
Jean Ritchie and George Pickow, have a film "Oss Oss Wee Oss", that shows some of the Padstow festivities but I don't know if there is anything similar for Helston (apart from the video we took).
You really need to experience it in person to fully appreciate it.
Robyn