Dear Nasratullah Habibi Please, find the attached files. It is about PEG-6000. So you have now, how to prepare the osmotic potential from PEG-6000 too. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC366375/pdf/plntphys00228-0098.pdf I also send you an excel file that includes quantity calculation of PEG-6000. Please let me know, maybe I can do more.
Find the attached file in bellow link. This file is provided by @Elias Soltani and has a very simple user. You can calculate the amount of PEG by entering the temperature and water potential (bar) of the target solution. (bar = MPa * 10).