I purchase the old style paper bowl screws 250 at a time, they aren't terribly expensive that way. Same with the old style fuel inlet seals. If you needed just a few I'd be happy to help. Same with VS lids, etc.
The reusable nylon stuff seems to work well on newer carbs but many times they make for a weep on the older stuff.
If the metering block doesn't have a ported vac spot, you can drill a feed hole in the metering block face. 1/4-28 is the size to tap to for standard fittings. I would make sure you are using a primary block however before doing that. Not the end of the world, but using a secondary block with a raised angle channel can cause some issues on the primary side.