Oh yes these screws, yes they are very tight. A real nice fitting impact will help although you'll lose a lot of the power from the length. Another thing to try (if I recall I tried this and I think it's what finally worked) is to get a solid bite and apply some force to the back of the screwdriver and some torque like your trying to remove it and then tap the back of the screwdriver with a hammer kinda like how an impact screwdriver works although not as good but we can't get an impact screwdriver in there anyway. You can kind of time your extra torque pulls with the hammer hits. Yes this is easier with two people. I can't recall if they have loctite or not but can't hurt apply some heat to them with a soldering iron for instance.