Woolly Thyme as Lawn in Zone 6

I am just finishing my new home and wanted to plant woolly thyme instead of a lawn. Can you please give me some idea on how much area one of your 'plugs' would spread to cover in one growing season. I live on the south shore of Nova Scotia, Canada.
I was thinking of ordering one plug per square foot thinking that I would be completely grown in sometime in the second year. Is this a reasonable expectation?

We recommend planting thyme on six inch (15cm) centers, because otherwise the chore of keeping the bare ground between the plugs weeded might get too much for you. This would mean 4 plugs per square foot (900 square centimeters)
Your expectation of having it grown in in the second year is reasonable, but I think you would be happier if it grew in after the first year -hence the six inch center recommendation. Stepping on the plants to do the weeding will slow their growth and the ones with the most weed competition will have to be stepped on most.... A winter mulch of weed free straw would be a big help.