Damm... you really are the Miester, that is 57gr + 2 screws and plastic nuts.

The cheapest and fastest way to measure balance weight would have been using same size tires and heigh gauge on the middle left and right. If you are using 2 standard servo size (ex, S9451) and receiver (ex, Futaba R131iP), you will need about 120gr on the left. About 60gr as pictured is using 2 low profiles S9550 servo with 1 Ptransponder underneath throttle servo (about 10gr) and regular Futaba PCM 131iP receiver that given me more convidence of L/R balance.

Using the new hudy tweak board from HSP-108255 will gives more accurate reading but then of course if you could afford 4x digital scales that would be nicer