I guess I'm kind of looking at the Canadian situation. We have a social assistance programs and minimum wages that are more generous than the USA. The plight of the Canadian poor is not as great--unless there is an addiction issue, but that's another story.
My family would be classified as "lower middle class." We get a government subsidy of $350 per month per child. This does make a big difference into our life options.
One thing I like about a full UBI is that if an individual or family cannot make ends meet on a government stipend, that would be reason for an investigation and possible intervention. Otherwise the government stays out of the individual/family affairs.
But for Canada, especially my province of Alberta, start with $200 a month for everyone. Watch the economy; raise it by another $100 if it seems most jobs are being filled. Give businesses time to get used to the idea that they will be less able to hold employees as hostages*. Make reductions to other social assistance programs.
The goal should be that everyone should be able to afford a small place, food, TV and cellphone, and a little recreation money. If they want more things, they need to find a job.
*A UBI will be a great motivator to cultivate better managers. This will be an immense benefit to the economy.