First off, there should be 28-needles, a spacer, and two clips per wrist pin. I took an old bed sheet and duct taped it over the top of the cylinders. Using a razor blade I cut a slit in the sheet for the pistons to come through. Finally, I duct taped the sheet just under the piston on the connecting rod. This made it impossible to loose anything in the case. A little prep time saves a whole lot of aggravation.
Before you close her up account for all your clips, needles and spacers. Remove all tape and shop rags. I suggest you install caged bearings upon piston installation. You don't need the spacer/washer upon installation of the caged bearings.
Take your time, it's not bad. Good luck.