what is the correct refrigerant capacityfor R12 in a w126? (R4 compressor)

i have seen;

1) on the red sticker on top of the radiator-3.3lbs
2) FSM cd-1800 grams-2.87 lbs
3) my indy's snap on cd - 3.5 lbs
4) this forum 2.2 lbs

this is a big difference! anyone?

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1993 Mercedes Benz 300D 2.5 205K (ex wife's)
1984 Mercedes Benz 300SD 320K (SOLD)
2004 Mercedes Benz C240 75K
1995 GMC Sierra 2WD 5.7L 188K
1983 Mercedes Benz 300SD 239K (SOLD)
1987 BMW 325i 220K (SOLD FOR SALVAGE)

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