How to make my small grid ship hover?

Solution 1:

I'm not going to accept this answer, because it's not complete, but I have found a hack-job answer to this:

First of all, thrust override is a nonstarter: if any thrusters have override set, the inertia damper completely shuts off (google for videos of cats having a leash put on for a graphical representation of what this is like).

Putting thrusters on the subgrid itself did the trick... sort of. This is probably good enough for subgrids that remain aligned in critical axes with the root grid, but in my particular case the drills are on hinges with a 180-degree range of motion. Slapping two thrusters on each drill - one pointed retrograde to the drillhead, the other prograde - and switching them on/off based on the orientation of the drills is the functional hack that I have going right now.

The process is: Fly with retrograde thrusters on and drills in upright position. Gain altitude over target. Turn off retrograde thrusters, activate hinges. Wait for drills to lock into downward, 'drilling' position. Turn on prograde thrusters, descend to target and begin drilling.

The process is reversed once you're full of ore.

Obviously this isn't necessary for spacecraft, because you can move the ship in any direction so drill orientation becomes moot.