While looking for a caliper to take a picture of, I noticed two of my other calipers have a stronger spring than the one I chose to take the picture with. The one pictured has a thinner spring like yours, I don't know which ones may have been replaced or if they upgraded to a stronger spring down the road sometime, the stronger spring does give it a more positive feel though. Thick "fender washers" make a good choice between the lever arm and castle nut and helps get rid of the slop between the lever arm and the engagement pins. If you need a pinch bolt for your brake cable, they can be found at most bicycle shops, might not be "correct" but if you don't have one or you are waiting to get one, it's a quick fix until the "correct" one arrives.