>I've done it and it took a while to process, but it did finish without any error (with around 4,600 records). The memory consumption was around 150MB (way lower than the 800+MB in the automated process).
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>>Having all the necessary tables created have you tried a manual mailmerge? How does it perform?

Did you compare the manual process with a automated program to just do the mailmerge (e.g. starting from creating word object) ?