Sam:
Taking a quick look at the library part, in the Parameters Script there is a command (open("text", "Joists(13).txt", "separator='\t', mode=ro, Library")) to the text file "Joists(13).txt" where these values are stored. So it should be possible to edit this file to change the values. This will take some knowledge of GDL and how the
Open command works (pages 259-260 of the GDL Reference Guide).
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David