AFTMA DT WF LEVEL
1 -- -- I
2 -- -- H
3 IFI IFG G
4 HFH HFG F
5 HEH HEG E
6 HDH HDG D
7 HCH HCF C
8 GBG GBF B
9 GAG GAF A
10 G2AG G2AF 2A
11 G3AG G3AF 3A
12 G4AG G4AF 4A
Sorry can not get it to line up exactly
You may well be thinking about the old Kingfisher & Hardy Corona line ratings. As I remember
they were Size 1 2 3 & 4 with 1 the lightest & 4 the heaviest.
Again if I remember rightly & I last used a Kingfisher 40odd years ago so I may be a bit out.
Kingfisher 2 would be about a 6wt & a 3 a 7/8 wt
Look at this article from Reed Curry's fine website & you will find your answer I am sure.
http://www.overmywaders.com/extracts...framSchott.pdf
Hope this helps
Tight Lines