Sacrilege.....get yourself an IROOA for a retro look, or a 12585 (both fit E39 35 and 50mm's), or a 12504 (35mm only). You wouldn't put cheap aftermarket Chinese stuff on your Porsche, would you?
I have one of those for my 135mm Elmar.....yup, they work fine (although the threading can be stiff and tough to start, especially when new.) Clamp-on beats screw-on hands down...
You paid damn good money for that 'cron, it deserves better.😉