My understanding is the well up test is not as good as the drip test. Since when you advance your pump from an indicated 6-7 degrees things get much worse it becomes interesting. Also that very rough idle had caught my attention much earlier. I wonder if it might be productive to read and post the various milli volt readings from the cylinders. I am starting to wonder if someone might have played with the element adjustments either accidently or on purpose not knowing what they were doing. There are recorded instances of past owners getting the number one element off by trying to do the timing improperly.. They removed and reinstalled the part with two nuts. Or perhaps all it takes is too much force applied when hooking up the injector line again. If there is a vast difference in milli volt readings between cylinder 1 and the others, say 3 milli volts,with a few other minumin tests to verify the accuracy of the reading you have it. Also you will probably be able to correct it unless they removed the shims underneath. Not too likely in my opinion. I really would stop at this point and read the heat in each cylinder with the milli volt method. Costs nothing and may reveal a lot. Something odd is going on here it seems. Logic would seem to indicate since the chain was not installed properly perhaps someone fooled around trying to get the engine to run better. I hope not but it is detectable with the reading of the glow plugs and a few simple tests if the glow plug voltages are off value. If the glow plug voltages are pretty uniform in comparison to each other you have cleared the pump itself pretty well. I suspect your pump is not going to make the test but hope I am wrong. As for a drip test tool. Just get an injector line and fitting from a junker and make your own. I am not sure if the well up test can be way off but there has been some information posted that it can be negatively affected by the delivery valve. To what extent I am not aware. Common sense would almost say certainly not to the extent you are seeing but I may be wrong about even that. In the old days a thread like this could go on and on without being resolved. It is no longer required as we now know how to eliminate things lets say in a more scientific manner. The underlying question is will the milli volt system become a generally used tool? I personally know of no other system other than substitution and guessing for these old indirect non computor diesels. As for timing by ear? Not a particularily good ideal if what I suspect is wrong. You will never have good fuel milage for starters plus really good cold starts will be affected to some extent next winter. Or just could be better. My best guess is cylinders 2,3, and four are advanced with number one displaying a retarded effect..That why the car runs fast for a 240d with a poor idle. Your millivolt readings would reflect that by a lower voltage on #1 cylinder than the others. Sorry about the long rambling post...