Wittek clamps

[3W Hank]

Questions on Wittek clamps.
First. Are they numbered in sizes ?
For example I has 5/16” rubber in US made fuel lines betwwen the LZ carbs but plan to has 3/8” from tank under car to firewall.
I also has water tubes ( FH ) and I think OD on rubber might be round 2.3”.
Any suggested sizes ?

Then, how are the periods, can one see dates, if had the older holes or cadmid surface or steel.

I has bought some from 2 ( 3 ) places but will get them soon but now I bought 3/8” as he said work fine and dated 4/48. No holes but look like a steel shell.
Others I bought, seen pictures is cadmid surface some with holes, some not.
No detail on numbers ( size ) or date.
Will soon know.

I has only 2 of the larger ones ( 60 mm )
But I need 10 more.
Its not that easy try figure all this out and find the parts.
Some of my buddys say I’m a nut.
Shore, I can go to Walmart, but its not that fun.