Trying to keep the wrenches that came with my router in position for tightening or loosening the collet used to drive me crazy. The nuts are so widely spaced that the slim wrenches would often slip out of place.
Fortunately, I discovered a solution at my local hardware store: basin mack gaskets, which are stepped rubber washers used while installing sinks.
Fasten a gasket on each side of one wrench with spray adhesive or contact cement. Then use a utility knife to sculpt the opening.
During use, the gasket-covered wrench goes on the shaft nut. One gasket holds this wrench away from the motor housing. The other gasket acts as a platform for the wrench that goes on the collet nut. If the gaskets are too thick to properly align the wrenches, just slice them thinner. One side of this wrench works for tightening; flip it over for loosening.