Hi @kristofvt,
If you plan to use coherences better not get the master as the first image as mentioned on my last post, as coherence decorrelates with time.
Master is the Read 1 and slave Read 2.
I have put available some scripts that could help you to do so, you only need to change the xml to use in one of the steps. Not sure you needed. It can be found in the thread: Snap2stamps package: a free tool to automate the SNAP-StaMPS Workflow .
If you may want me to help you to customise the processing for your particular case, contact me.
Regarding the procedure you mentioned, at first sight it seems fine to me.
I hope this helps.