I think an even better solution to the pinching on the grips is to simplify those thin gaps out. There wouldn't be a good way to model them in the lowpoly so that it projects well.
I had similar pain in my left arm/chest. It was a pinched nerve due to an inflamed disc. Go see a doctor though. Seriously, the internet is not a replacement for a Doctor.
I use really basic brushes. Detailing is mostly clay tubes. Metal dings are usually the standard bush and sometimes I use the pinch brush to add a crease.
If I understand correctly, try selecting an edge ring and then Connect. Set the edge count to 2 and adjust the pinching to what you want. Then do the same to the perpendicular edges.
Looking really nice, Got any advice on doing fur? Currently just using snakehook and pinch but not getting as clean results as you. Cant wait to see it finished :)
Don't sculpt in that way! That will stretch your geometry. Use Orb brush, gogle it, its free. Pinch is good for sharpening details and edges like on rock or something, not for the wood.
Oniram is right on the money. If you let go of shift while smoothing zBrush will use a different smoothing algorithm that takes care of poles and pinches much much better.