You have to understand that
A) I have bright blonde hair
B) I've never had a TopLace system.

So I'm not the best person to answer this but I've read many of Paul's posts and he has said before that knots have never been an issue on his fullcaps.

Its one of those things you can become obsessed by though. I never thought about knots until I started to read the forums.
I think if you start looking for them, then you'll see them and they'll concern you.

One of my favourite hairlines ever is a TopLace system worn by Reubin.
If you search his posts, you may find details of what he orders: