Your Engines consume about 330-360l/h each in the Climb and about 230 to 280 in Cruise. So if you Calculate Conservatively you say 650l/h in Total. Your normal Sortie from the Rear of the Map, Climb to 5k in Summer and 6k in Autumn and Winter, entry into Enemy Territory, Doglegs etc. will give you roughly 1:15h to 1:45h of Flight Time. Now add a healthy 30 or 45 Minutes of Reserve and you get 2:30h.
That gives 1625l of Fuel if you are extremely Pessimistic to last you 2:30. Now, realistically in 1:45h and a normal 520l/h you will only really need about 900l of Fuel. My Standard Loadout therefore is a still Conservative 1200l for all Circumstances and is enough for all Bomb Loads
WHERE THE HELL DO YOU THINK TO REQUIRE AN EXTRA 3000!!! Litres? Are you trying to to Bomb Thailand?
Anyways; For Take-Off if you want a nice DC-4 style Floaty Type Take-Off you need:
Full Power, so 2600RPM and 1.4ata
30 Degrees or 50% Flaps
50% on Oil and Water Rads
The He-111 has a very Effective Elevator as soon as the Engines are under Load.
Push Fully Forward as soon as you begin your Take-Off Roll
The Tail comes up IMMEDIATELY
Keep the Aircraft exactly Level to quickly build up Speed
As you approach 150 to 200 (depending on Load Conditions) the Aircraft will Lift off with very little Back Pressure on the Stick
Keep the Aircraft in Ground Effect (about 3 to 7m off the Ground) and let it accelerate while retracting the Gear
As soon as the Gear is Up and Speed above 200kph
Retract the Flaps to 25% or 15 degrees
Power down to 1.25 ata (85%) and RPM to 2400 (85%)
Let the Aircraft reach 215kph
Fully retract the Flaps
Let the Aircraft reach between 230 and 250kph and enter a Climb to Maintain that Speed.
It should look somewhat like this: