We could make a land value tax constitute any amount we’d like.
Just take the value you want it to produce, divide by the assessed value of all of the land, and you have your tax rate.
That’s not an interesting question, though. The interesting part is whether or not that’s reasonable or fair, and to explore who wins and loses.
That's how my city determines property tax rates! Cities in my province are not allowed to run a deficit. So every year, the city look as assessed value of all properties, how much budget it needs for the year, divides the two, and voila! Tax rate!
It's actually a bit more complicated because the residential and commercial tax rates are different and the city has revenue sources other than property taxes, but it is largely like that.
Remember the valuation is based on the rental value of the land, not the capital purchase of the land.
If I understand correctly, the point of this article (one of several) is just to establish that a land tax would constitute a large amount of money. I get the impression the article was supposed to merely establish whether a land tax would generate a substantial amount of money whether good or bad, though admittedly the author tips his hand as to what his conclusion is. I'm also hopeful for the next article, I've been wanting a good reference on Georgism that wasn't book length to point people at for years.