Marty, the reason I said rhyme is optional, (as you said optional in general practice) is to make the case that rhyme is a minor issue, and in the bush poetry, writing rhyme is usually managed reasonably well. But poetry, all poetry, is metric writing according to Stephen Fry. Not so easy to understand well and unfortunately there are bush poetry writers who do not manage the metre very well at all. I study it carefully but it still is a difficult process for me.
Look up William McGonagall,
The Tay Bridge Disaster and you will find out what I am talking about.
here's a sample from that poem .
When the train left Edinborough
The passengers' hearts were light and felt no sorrow,
But Boreas blew a terrific gale,
Which made their hearts for to quail,
And many of the passengers did say -
'I hope God will send us safe across the bridge of Tay'
Perfect rhyme but the metre is hopelessly inept.
So I think that discussing or analysing rhyme is not very useful, but analysing and discussing metric structure is most important.
Stephen, Contrary to what some might think,. I actually enjoy the spirit and fun of bush poetry, I just wish we could sometimes be more flexible in thinking about the issues.
Maureen. Maybe Bill was never married before, perhaps that could explain his robust health in old age, no stress
And finally, I reckon that the spirit, the passion, the authentic feeling and voice, trump all the technical niceties, if that is what it takes to make poetry.