The nut for the 2.5″ bolt should be left extremely loose almost touching the roller but not all the way. Make sure these nuts don’t interfere with the small nut slots, if they do put the small nuts in now. Put all the rollers on there rails and make sure they all slide equally well. There should be tension when inserting the rail and all the bearings should touch.
There is no tension when inserting rail and the bearings do not touch unless I move the rail side to side.