Is the clutch lever pulling in okay?
When i changed my clutch plates a few months ago, and replaced the pressure plate, after tightening the clutch spring bolts i put it all back together and the lever was solid, which properly confused me for a while.
So i took the cover off again, stared at it really sternly for another while, then slackened the spring bolts again, then went round the other side to undo the clutch cable adjuster nut, and totally backed off the adjuster screw. I then torqued up the spring bolts again and adjusted the cable adjuster screw to where it should be and then it was all sweet.
What i'd done before was tighten the pressure plate that obviously pushes against the clutch plates, but they in turn were sitting on that cable adjuster screw which was still set in a position to cater for worn out plates rather than being backed off to compensate for the thicker pads on the new plates.
Just a thought.
I'm no expert on this but i wouldn't think these particular springs were the cause of your issue, although it won't hurt changing them if it's apart anyway.
Now you've hinted at your problem then the higher powers on here will probably be along soon to give your more info at what could be wrong.