I am wondering whether the vinten vision 3 springs are compatible with the gitzo g1380? For the springs that come with the 1380 their is a big jump between 4 lbs and 11 lbs.... I think the vinten 4 is rated at about 8 lbs which is what I am looking for.

thank you in advance!

This article claims that they are identical:

A Measure of SupportRobert M. Goodman, Robert M. Goodman, Robert M. Goodman (http://www.dv.com/article/11548)

See the Vinten section.