Wobble socket or wobble extension. Used with an extension and a small impact driver has been mentioned.

I could not find the link for photos but in any case don't really understand the problem. I've removed driveshafts from dozens 240 Volvos and have never used any of the tools the OP mentioned. What is needed are two box end longish (10-12 inches or so) wrenches of the proper size. If Art's Volvos are earlier models the wrenches would indeed be fractional - later cars have metric hardware - and the sizes needed changed over the years with the metric bolts/nuts. Most of the time the "squeeze the two wrenches together" technique works but when they are too tight here's what I do. I rotate the driveshaft so the head of the bolt (the head should be facing the front of the car if installed correctly) over to the passenger side so the holding wrench end will jam against the floor or the exhaust and then with the second box wrench installed on the nut at an angle that will allow me to get under it and use my "mass" to push the wrench upward (counter-clockwise). Keep your palms open to protect the knuckles. You can use the same technique on the driver's side to tighten the nuts on re-installation. A pair of good fitting 12 point box ends will suffice but if a 6 point is available and offers a workable angle so much the better. - Dave