@Rojer Not sure how many hours, exactly, but I believe I did it over the span of a few days. No problems with the number of objects - just gets confusing if you decide to un-group and then re-group. Infinite group drilldown cannot come soon enough!
TY for the reply. Perhaps my issue is caused by my computer versus the system. But with 12GB of RAM, I would have thought that sufficient. But now a full 7yrs old, perhaps it’s time for a new computer anyway.