The Kwaremont will be super busy and there's no good-sized locality to soak up some of the crowds like Geraardsbergen used to do for the Muur.
I would say you'll need three to four hours to select and hold a good spot. Try to watch some videos in order to help you with that, because it's a long climb and you don't want to waste time on the day.
On the Kwaremont, the tree-lined section before the village crossroads is a good place because the riders are slow and funnelled here close to the top. It's nicely sheltered by trees and I was well protected there during the worst of the apocalyptic 2010 edition of Kuurne Brussel Kuurne. But it will be very busy.
Walking or cycling are the best options if you don't mind the effort. The landscape is pretty nice down there though there's only one bridge crossing anywhere near Berchem village.
Take an umbrella (it rarely rains on Ronde day nowadays, but you never know) and some food and drink. Forget needing the toilet.
I don't bother with the Ronde these days because pretty much all of the E17/E40 triangle of Flanders shuts down making it hard to reach on the day. I prefer to do the Omloop Het Nieuwsblad / Kuurne-Brussel-Kuurne double.