A long time ago I'd buy Columbus SL and SP tubing in bulk volume to get a better price. SL chain stays varied in weight. I would weigh each one so I could find the ones that weighted about the same to pair them together, What I not perfectly recall is that the variation was between 140 and 170 grams each. I would then use them accordingly to put my lighter customers/students on the lighter chain stays.

Another variable is that stated wall thicknesses of almost any brand of tube and actual measured wall thickness seldom agreed. And of course where the butts are located and where they are supposed to be according to the manufacture was another variable. And how long the butts are on any given tube model could vary considerably and then how much is trimmed off when mitering becomes another variable on frame weight.