The controller should take care of applying the length offsets when you call the new tool number and new H number. The displays do not need to be programmed manually at all (with G92), unless you are running a very old machine with no work offsets. What kind of control is it?
If you must use G92, why would you call the tool home position Z0? Why not set it to be the distance of the standard toolholder above the part surface? Either that, or make your tool offsets the full distance from tool home, to the part surface (Z0). This is risky because the tool can rapid right into the part if you have not set a Z rapid clearance plane at the beginning of each process for each tool. You would be better to set the length offsets to a rapid plane 25 or 50 mm above the part (use a gage block or something) and at least then, your tool will move to this rapid clearance plane when the length offset executes.
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)