The Devitt-Caine Mk. IV MMR houses a crew of three soldiers:
Driver (Seat 1)
Controls the movement of the vehicle, and can see the remaining fuel in the tank
Gunner (Seat 2)
The gunner aims, fires, and reload the mortar. The only crew member who can see the ammo type loaded.
Use Mouse Scroll Wheel to adjust the range
Switch ammo types by pressing F
Commander (Seat 3)
The commander is able to view the battlefield with Binoculars, telling the gunner where enemy structures or vehicles are to shoot at, while also reporting on where the shells land to ensure they hit their target. They have no hatch to hide.
The turret is open top making the commander and gunner exposed to small arms fire and shrapnel.
Mounted on a rotating platform inside the open-top turret (can rotate 360 degrees, turns 10° per second)
The Devitt-Caine Mk. IV MMR has 1950 HP and is disabled under 30% health. It has "Heavy Armor" resistance: it can soak small arms fire, shrapnel, and 12.7mm machine guns, and it is immune to Flamethrowers. But heavy explosives and anti-tank weaponry are a real threat to it. It has subsystems that have a chance to be disabled by heavy explosives and anti-tank weaponry if hit specifically: Tracks: 30% (Anti-Tank Mines always disable them), Fuel Tank: 25%, Turret/Cannon: 20%. It has Tank Armor. With it, in best case scenario, penetrating projectiles only have a 30% chance of penetrating and doing damage. That chance goes up quickly if the armor is worn or if it is shot from up close, or on the side or rear from a direct angle, or with ammo that has penetration bonuses. It takes 135 Basic Materials to fully repair it from 1% to 100% health with a Hammer. Its health, subsystems, and Tank Armor can be instantly repaired at a Garage for 100 Basic Materials.
Due to its armament, the Devitt-Caine Mk. IV MMR can be used either as a short-range artillery piece, or an infantry support role. The vehicle has the ammo capacity allowing it to provide enough firepower to damage small defensive structures, as well as having enough ammo for anti-infantry tactics, such as attacking them directly, or illuminating their position.
If the crew ever comes into a dangerous situation (either from artillery retaliation, or being flanked by enemy infantry), the crew should rely on the vehicle's mobility to escape. This is especially true if they are equipped with AT weaponry, where the damage to them will either slow it down, disable it, or outright kill it.
Although it is possible to use a Light Tank without a Commander, it's not recommended as it will limit your awareness on the battlefield.
Due to being classified as an artillery piece, the rounds are affected by wind and dispersion, so either the Gunner or Spotter needs to pay attention to where their shots are landing (preferably with binoculars) in order to make sure their shots are hitting their targets.
Mortar weaponry, while good, has low High Explosive damage, meaning that a single mortar tube is typically not enough to destroy larger defensive structures, such as bunker pieces. Additionally, due to it able to fire HE rounds, it will get retaliated by bunker pieces with Howitzer Garrisons connected to it. Due it placement in the tech tree, it is more likely the mortar crew will face up against these types of targets.
As such crews will need to choose their targets wisely, or face near-certain destruction. If they are unable to, then an infantry support role is highly recommended.
Despite being used in a support role (i.e. behind the actual frontline), crews should still equip themselves in case they are out-flanked. For the Gunner, it is possible for them to forgo the Basic Materials in order to hold more mortar shells.
The Devitt chassis is likely based on the French Cavalry tank the SOMUA S35 or its predecessor the Char D2
The Devitt-Caine Mk. IV MMR from the front
The Devitt-Caine Mk. IV MMR from the rear
The Devitt-Caine Mk. IV MMR with a Commander and Gunner (exposed to the outside)