I opened up the library part and it looks like it has been hard coded with absolute values e.g. you would have to go step by step through the GDL scripts to make them parametric or change them to the values you want.
As has been suggested, if this is a one off case, you could just convert the object to Morphs and then stretch the morphs to what you need. If it's a repeating object then you could consider editing the GDL, or if you don't know enough or anything of GDL an alternative would be to save the morphed object as a module file (.MOD), that way should you need to change it there is only the one instance to alter. Once created you can Hotlink the Module file into your model.
With the Module option, I would open a new file, add the court on the ground floor, convert it to a morph, stretch as required and finally Save As a new module file. You can then return to you main project and import it with File > External Content > Place Hotlink.
This may help:
https://help.graphisoft.com/AC/24/INT/#t=_AC24_Help%2F080_Collaboration%2F080_Collaboration-58.htm&r...
Apple iMac Intel i9 / macOS Sonoma / AC27UKI (most recent builds.. if they work)
