It's hard to compare which is heavier, blacks or clears, since the action is so much different on a tactile switch. Instead I made a point about the difference between clear stem + clear spring vs. clear stem + black spring, using the force graphs of black/black and clear/clear. As key travel increases beyond 2.5mm, the key mechanics are the same for both black/black and clear/clear, except for the difference in spring. That's why bottom-out force for that graph is useful for comparing the relative strength of these springs. Similarly, you could make the case that red, blue, and brown switches all use the same spring, since their force graphs are a close match beyond 2.5mm and all bottom out at 60 cN. This is despite the fact that blue switches have a higher activation point than reds or browns.