This is a great answer thank you! I had not paid attention to the other options in the 'add fields' drop down menu - I am sure this will be very useful for many more applications in other schedules.
I also note that even though the parameter is taken from e.g. 'window 24' it applies to all the windows, including e.g. 'double window 24' so I don't need to add one row for each window type.
As to why, I appreciate it is a strange request, however I have run into similar problems a number of times, where I know the information exists, but cannot figure out how to extract it to a schedule. Hopefully that will now change following your advice. In this instance, I am coordinating the windows to block opening sizes, and the contractor is using different size packers in different locations at the heads and sills to make up the difference between the full block and the window unit (the window units have different height requirements to meet - e.g. distance from finished floor level, which don't neatly tie in with full block courses). I wanted to extract the tolerances specifically so I could check I had the right tolerances in the right place, and convey this information to the contactor.
Thanks again for your reply,
Archicad 23 Solo, Dell Precision 5540, Windows 10 Pro, Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz 2.59 GHz, 32GB RAM