A long strip of phosphor bronze (brass or any metal would do), fluxed and coated at the end with a thin smear of solder. The weight has to fit on top of this soldered joint and it it is too thick, it will not be possible to for the latches on stalks to hold the weight down.

Use pliers or tweezers to act as a heat sink and to hold the new strip steady when the heat is applied. Another heatsink is required at the lower end, but preventing burnt fingers is a priority - so the soldering iron must not remain in contact for long - just long enough to melt the smears of solder and thats it. Any longer and the plastic rivets that are holding the strips down (near the L and R) will melt.