If you are serious about the Weber 32/36 buy it from Pierce Manifolds https://www.piercemanifolds.com/product_p/k660.htm. This is the kit that will work for your L20B.
I have been buying Weber's and Weber Parts from Pierce Manifolds since the 1970s. Good people and excellent Datsun knowledge.my last new Weber 32/36 is on my 1986 720 with a Z24 5 speed, installed in Battle Mountain Nevada in 2011 and it is still running great to day in Tolleson Arizona.
Weber's are simple carbs, I have a stack of of used Weber's I use for parts. Weber's need to be re jetted for high altitude. If you call Pierce Manifolds talk to them about the re jetting for your altitude if it is necessary they will advise you also ask if they can sell you the jets you need if your altitude requires re jetting.
Battle Mountain Nevada has an altitude of 4,500 feet and Tolleson Arizona has an altitude of 1,000 feet. I did not re jet for this altitude change when I moved back home to Tolleson. Stock jets that shipped in the new Weber are still in it today.
I hope this helps.