For all the time and effort you spend in trying to get a GS file to play passably on a computer, it would be faster and more accurate to use a Roland module, the thing the file was originally developed for...!

Try to see if you can pick up a used MGS-64 rack module or higher, they can be found very inexpensively (my favorite is the SC880)....

No more worrying about CC codes or NRPNs, Reverb type sys-ex, etc., etc.. Why use an expensive laptop or computer to do what a cheap module can do better?