The next step is to bolt up and torque all the main caps (don't forget to oil the bolt threads) except for the cap containing the thrust bearing. Check your endplay again. If you don't have enough play, one of the caps is out of alignment. You can adjust the cap location slightly by tapping it lightly with a dead-blow hammer and then tightening the bolts back down.
Again, if the endplay is correct, you can install the last main cap-this one with the thrust bearing. Tap it into place but do not torque the cap bolts. Instead, rap the crank lightly, either forward or back, to align the thrust faces of the two bearing shells. Now tighten the bolts to the proper torque specs.
Once you have reached this point, you likely will notice the endplay has tightened up a bit. You can use a screwdriver placed between one of the main caps and a counterweight to help you move the crank. Do not use excessive force.
If there isn't enough endplay, you may need to reduce the thickness of the thrust face of the thrust bearing slightly. This can usually get you a thousandth or so. Lightly rub both faces of both halves of the thrust bearing on super-fine sandpaper that is being lubricated by a constant stream of fluid in your cleaning tank. It's also a good idea to use a surface block (or even a pane of glass) underneath the sandpaper to make sure you are sanding on an even plane. Remember, there's no way to tighten up a crank with too much endplay. That's usually a sign of too little fillet cut into the crank.