Thanks for these TSBs, but I have read them and am, unfortunately, in no better position than before.
As I understand it, the info included in the OTC manual chart gives what the working pressure of the system is, remove the fuel pump relay or the fuse, what connection should be made (fuel line schrader port is common). I have also found that if the system is a return one like you say is on the X308, then the compressor pressure should be about 10 lbs. less than the operating pressure of the injectors to obviate the return. Of course, I don’t know if that will work on this car this way or not. I also do not know what the operating pressure of the system is (52 lbs. seems to be common).
So, there is a lot I can surmise, but not a lot that I know for sure. Can you be more specific? Also you mention that I “will need to block the fuel return line to the tank somehow”. OK, but how do I do that. How did you do that.
Sorry to be this way, but I like to get as much info as possible before I embark on a project.