The light abrasives you mention are fine and will speed the clean up- just make sure you remove all the residue before installing the new seal. There really is a lot of latitude in seal placement, just make sure you have the new seal riding on an unworn portion of the shaft.

I always coat the shaft and seal with white lithium grease- nothing special about white lithium, it's just what I have available. This helps the seal slip into place without binding up. Always start the seal so that the shaft does not press all the way around the lip as there is the danger of it folding enough to allow the spring to come out of position which can result in leakage after installation.

Randy