An alternative is to open the tender and either (1) install a pot or (2) install a pair of resistors to bring the volume down. I don't recall if the pot is 5 k or 10 k. Use resistors of half that value, and place one between center wire and end wires.
If you don't want to drill a hole in tender floor (speaker will attract the shavings), just set the pot to the desired volume and wrap in electrical tape.
