I like Ishiwata - the relevant CrMo tubesets are 015, 017, 019 and 022, relating to weight of the tubeset, eg 015 weighs about 1.5kg and came with severe frame size and rider weight limits, 022 is equivalent to Reynolds 501 and hase served me well since 1986. There were also some high tensile carbon steel butted tubesets with 4 digit names, eg 0245
Kinky Cowboy*
*Batteries not included May contain traces of nuts Your milage may vary