I’ve been riding for a long time, and numbness has always been an issue. But not enough to keep me off my bike. I find a well broken-in B17 and ordinary (not cycling) shorts are fine for 100km rides. To tame the numbness, I get out of the saddle every few minutes to allow some circulation, and this helps a lot. I don’t wait until I start feeling numb before I get out of the saddle, I’ll simply get out of the saddle every 5 minutes or so. A riding position with a little more weight on my hands puts a little less weight on my backside.