The bearing clearance has already been set up by the time you have to worry about endplay. In this pic, you can see how to check it with a dial indicater. I use a broad tip on the indicator, it seems to work well.
Here are the two sets of wheels that I laced up today, the cad rims are for our 37EL and the cream wheels are for a 36 that belongs to a friend in Indiana. They are so pretty!!! I was going to lace up a pair of 16" 47 wheels, but the paint on the rims was not up to par.