My local MB dealership parts mgrs. told me that the 1.2 cap was standard issue early on. MB later switched to the 1.4 cap. I've been running a 1.4 cap which equates to roughly 20 lbs. It works fine.
1991 300-SEL - Model 126
M103 - SOHC
James Madison - Oppressors can tyrannize only when they achieve a standing army, an enslaved press, and a disarmed populace.
Liberty Firearms Training - After years of trying to regulate California criminals with a never ending stream of gun control laws they have still not given up with the belief that if they make something a crime that criminals will miraculously start obeying the law.