I have a Vinten Vision 3 that takes springs of various strengths, based on the camera's weight. I'l be using a heavier camera now, an HPX370, and will need a new spring.
It's a very common problem that people see the maximum camera weight listed for each spring, and buy one that's too strong for their camera.
#4 Red- up to 8.8 lbs
#5 Green - up to 11 lbs
#6 BLue - up to 13.2
#7 Violet -up to 15.4
#8 Red - up to 17.5
I think those are the most likely choices. I'm looking at the basic camera, lens, hood, and Diconic 90 battery, which total just under 13 lbs. Based on the chart I'd get a Blue, but based on experience I'm leaning toward the Green or even the Red.