I still think that the oil in the pockets will not be evacuated without some kind of actual flush.... it settled in the pockets because the refrigerant was able to pass it without taking it with it in the stream...think ' eddy '...or 'pool '..... and hooking up a recovery machine will not affect that physics situation... I say that taking oil out by physical removal of the receiver-dryer is probably the most direct and effective and cheapest way.
A recovery machine , if the TXvalve is left in place, can not get a significant flow of refrigerant ... it is not like it can cause turbulence in those pockets ... to stir up and mix it with the refrigerant...

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html