industrial engine meaning stationary operation (i.e. generator, big water pump ect). There should be specs for that equipment as to how level it needs to be, the engine is likely mounted level relative to the equipment mounting points so that the level of the equipment is the same as the engine, should give you a good range.
i would expect 4degrees to do much personally.
The R2.8 has a whole install manual and a video series but never mentions engine angle. From some of the hot-rod pages I've read it sounds like 3 degrees is the magic number for the carb to be level. A buddy on the LR site mentioned a little tilt to the tranny side would help with bleeding the coolant. I'm going to cut and maybe tack the mounts and see where the engine lands with weight on the whole thing. Right now it's hanging on the cherry picker with no weight at all on the chassis so could be closer to level when done.