dispatch.meta patch, manual installation.
There are 3 mandatory and 6 optional steps to this instruction.

1. Open \mods\update\update.rpf\common\data\dispatch.meta
2. Search (Ctrl+F for) "AMBULANCE" until you find <Vehicle> entry with AMBULANCE in its <Name>
3. Replace the entire <Vehicle> entry with the following:

		<Vehicle>
			<Name>AMBULANCE</Name>
			<ConditionalVehicleSets>
				<!-- Modified by [MRSA Pack] -->
				<!-- Remove the entries between Start and End tags if uninstalling the mod manually -->
				<Item>
					<VehicleModels>
						<Vehicle>ambulance</Vehicle>
						<!-- Start -->
						<Vehicle>ambulance2</Vehicle>
						<!-- End -->
					</VehicleModels>
					<PedModels>
						<Ped>S_M_M_Paramedic_01</Ped>
						<!-- Start -->
						<!-- <Ped>S_F_Y_Paramedic_01</Ped> -->
						<!-- End -->
					</PedModels>
				</Item>
				<!-- Start -->
				<Item>
					<ZoneType>VEHICLE_RESPONSE_COUNTRYSIDE</ZoneType>
					<VehicleModels>
						<Vehicle>ambulance</Vehicle>
					</VehicleModels>
					<PedModels>
						<Ped>S_M_M_Paramedic_01</Ped>
						<!-- <Ped>S_M_M_Paramedic_02</Ped> -->
						<!-- <Ped>S_F_Y_Paramedic_01</Ped> -->
					</PedModels>
				</Item>
				<!-- End -->
			</ConditionalVehicleSets>
		</Vehicle>

Optionally do following edits,
These makes ambulance response times longer
4. Search (Ctrl+F for) "AmbulanceSpawnDelayMin"
5. Set numbers to the following:

		<SLOW value="90"/>
		<MEDIUM value="45"/>
		<FAST value="20"/>

6. Search (Ctrl+F for) "AmbulanceSpawnDelayMax"
7. Set numbers to the following:

		<SLOW value="180"/>
		<MEDIUM value="80"/>
		<FAST value="45"/>

Finally,
This one makes both EMS and Fire Department respond to medical emergencies, in 3 people crews instead of just 2.
8. Search (Ctrl+F for) "DT_AmbulanceDepartment" in <EmergencyResponses>
9. Set the entry to the following:

		<Item>
			<!-- Modified by [MRSA Pack] -->
			<DispatchType>DT_AmbulanceDepartment</DispatchType>
			<!-- Original: 2	-->
			<NumPedsToSpawn value="3"/>
			<DispatchVehicleSets>
				<Dispatch>AMBULANCE</Dispatch>
				<Dispatch>FIRE_TRUCK</Dispatch>
			</DispatchVehicleSets>
		</Item>