This is a not very hard open source project.
I have a ubuntu Linux environment, and the source code has already been downloaded from github and built successfully.
I also have reviewed the code, not very hard, so I could complete it in 2 days more or less with full time, I think.
BTW, according to the logic in the project, before you can get the USB scale list, you must add the Vendor ID and Product ID for that USB scale in the scales.h and the .rule file.
So, I do not know if that meets your requirement; and at the same time, your requirement that, to display the weight of all the USB scale, will be done without any problems.
Thank you.