Now that it seems that OS nva for 20-40 FP with .135 thick spray bar is no longer being made, is there any other nva’s available in the same size? Most others seem to be .157 thick

It's 3.5mm.  I don't know if anyone else makes it, but you should check with Randy Smith -- he seems to have a good stock of parts.  Ebay may be your friend, too, but the popularity of OS CL accessories seems to have gone up -- I think there's a lot of their FP and LA engines that are finding their way into our hands, creating demand.