I would think with less clearance there would be an advantage for cam bushings lubrication and quantity of oil to cool piston...
There is a lip seal conversion that the Gold Star guys sometimes do to earlier quill fed engines (pre DB) but the crank needs to be out of the bike to do it properly.
It involves machining the timing case to accept a lip seal, pressing a stub into the end of the timing side mainshaft and then machining it Concentric
and to the size that fits the lip seal. I've done it on a couple of engines during overhaul. BSA found that it significantly improved big end life on the GS engines. So, it's worth doing if the engine is already apart but I'm not sure it's worth it in your case on an assembled bike.
For a little perspective, Enfields used a quill with a cork seal on their plain bearing twins!! But I'm not suggesting any such thing partly because it always seemed to me like a shockingly bad idea but also because there isn't enough room for it in your B33.