Canada is now vaccinating a higher proportion of its population daily than the U.S.

[Valcazar]

Is the percentage of vaccinated people much different?

Not hugely, no, if you count by "any shot".

And do not first shots provide a high degree of protection comparable to having had both shots? If so, then protection wise from vaccines there may not be much difference.

Yes. Evidence is that a large portion of the protection comes from the first shot. That said, there is a clear difference between one shot and two as far as anyone has been able to measure currently.

It certainly seems that one shot is sufficient to push R down below 1 once enough people are vaccinated. That said, you are going to get there much more quickly with the two shots for more of the population.