[Gaz64]

Yes, unlike an old Holley with it's steel inlet valve, the Webers inlet valve is very light and when submersed in fuel would be floating shut.
I always thought they were a "hanging ball" (non seated) like an early Holley.
It's a shame Weber doesn't make one smaller than .35, they must have thought there's not much difference between a .35 and 0.00.

A .35 is near enough to a number 80 drill bit, but you can get metric drills.
I have a set down to .3mm, so you could make you own .30mm bleeds.