My preferred method is to weight votes according to age: voters below, say, 30 would receive a more heavily weighted vote, voters 30 to 60 would get a less weighted vote, and those over 60 would retain their current single vote. For argument’s sake, you could multiply the vote of under-30s by 1.3 and that of 30- to 60-year-olds by 1.1. People’s ballot papers could be distinguished by colour – under-30s get blue, 30s to 60s green and oldies red – to make counting easier on election night.
I would vehemently endorse such a bill. Under the guise of ‘All Australians retire at x’. I’d propose that number to be ~70 years old.
Interestingly, our politics aren’t too bad at this. Only 4/226 members in parliament and senate are over this age (they’re all blokes of course). Contrast to the USA where this is a far bigger issue - over a third of their senators are over 70 and a fifth of their house members (not sure what the term for those is) are over 70.