I believe Large Drills are needed in the game, so here’s a suggestion on design and measurements:
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( ^ click to enlarge image ^ )
Note: If blocks are 2.5m, then my measurements should be accurate i think.

Trying to build large grid miners that can handle strong gravity almost always results with a ship that looks like a giant flying brick. Not that this is a bad thing cause they look cool, but it doesn’t offer much in the way of creativity or drilling efficiency as you have to plaster the front of your mining ship with 24 normal sized drills and modules. I also assume all those drills negatively impact server performance, not to mention a player’s PCU costs.

Pros:

Potentially less strain on server and player-pc performance
Opens up a whole new world for large grid mining ship creative building
Allows use of forward facing large thrusters, as normal drills don’t provide enough dig radius
Greatly reduces PCU costs
Will look really cool!

What about the Giant Drill?

The Giant Drill needs Rebels Components, so not a permanent tool to rely on
Looks to be used more for precision tunnel drilling
Upgrade Module doesn’t work with it.

Large Drills:

Should be 3×3×6 in size to match up with large thrusters, and not be too long as to avoid oversizing the ship.
3D models could be made by taking the model of a Normal Drill and scaling it up, cut off the port box, then attach the back end of a Large Hydrogen MK Thruster, then add in detail work to make it look right. You don’t have to go through the trouble of making a whole new model from scratch, unless you want to.

Dig Radius for MK Large Drills:

Left-Click dig radius (r= 13.75m) needs to be large enough to allow enough space for Large thrusters and some armor along the sides of the drill so we could benefit from having large reverse thruster power to reverse, break, or dampen with.
Right-Click dig radius(r= 41.25m) ~~im guessing is twice~~ is triple the radius of the Left-Click radius. ~~Im not really sure, so adjust measurements as you would like to.~~
Reason for MK: I chose MK for this measurement suggestion as i believe MK is where a player needs to progress too before being able to take advantage of large thrusters on their mining ship.

Large Upgrade Module:

Literally just the normal sized upgrade mod, but scaled up to 3×3×3.

Material Costs:

I dont know what ratio calculations you guys have for material costs, so im just going to guess.
For Large Drills, im guessing 10-18x that of a normal drill, since you can fit 18 normal drills inside the space of a Large Drill.
For Large Upgrade Modules, im guessing 15-27x that of normal upgrade mods, since you can fit 27 of them inside space of a Large Upgrade Mod.
Large Drills and Large Upgrade Mods should be pretty expensive to so that it takes a while for players to have the means to build them, and will lock new players out of being able to take advantage of them.

Tool Point Costs:

Large Drills should be 4-6 tool points, as they take up the work load of 4-5 normal sized drills. If you want to limit the number of Large Drills per grid, go with 5-6 for point costs.

Anywho, thats my suggestion, i really hope we get to see Large Drills in the game in the future as i think they’re really needed. If i knew how to model and mod for SE, id make the darn things myself xD