I just thought I should mention that I managed to get RBGTweak to work after installing ROTJc and d. After applying ROTJ, I found that my Object distance and bullet impact flashes had gone back to default no matter how many times I reset them.
Simple solution...kind of obvious...I am somewhat embarrassed, actually...but I thought I better post the result, even if it is over a week later.
ROTJ put another objdat.dat file into my Simpatch folder and that is the one that must be written to by RBGTweak. To change the file path, move RBGtweak.exe to a different location and start it up. The file path browser will come up and just look for the objdat.dat file in the Simpatch folder.
You can also just change the rbgt.INI file path with notepad.