Keep in mind that your fuel usage will be red until you pretty much reach cruising altitude and level off.
Going 4k VS will not cut it in some aircraft. Keep it around 2000-3000 depending on the aircraft while climbing. 250 up to 10k then increase to 300ish then transition to the cruising mach number. I do A320 crusing at .77. Seems to work out best for me.
If you are sitting on the ground in a long line of traffic, taxi with one engine. But be sure to start it before asking for takeoff. Do not start it once you are on the runway, ATC will not appreciate the delay.
I think it’s about finding a balance. Thicker air = more thrust but also more air resistance. Thinner air = less thrust but less air resistance. So you basically have to find a good balance between the two but also taking into account that the thinner the air, the less lift the wings generate so you need more speed higher up.
If you go on sim brief and file a flight plan with an actual departure time, it should give you accurate winds. although take abt more. In RL On the A320 we usually take 500KG to a 1 Ton of extra fuel for hoping around Europe, weather is unpredictable at the best of times. Its like that crazy ex who siphons fuel out your car :P.
I was in a similar situation 12hrs ago. Step climb with a low VS. Set trim to 52%. Keep in mind as the aircraft progresses, more fuel would be burnt and it would make the aircraft lighter so you would have reduced fuel flow thus the fuel would stil be enough for the flight.
@DeerCrusher told me to adjust the trim while cruising so the pink line inside the button goes away. I started doing this and was surprised at the fuel savings. Even on AP I now adjust the trim when cruising.
There’s no point in looking at those numbers during climb out. It will always be red.
The calculations it’s making are for that moment only. Your fuel burn is at its highest, your speed is not yet at cruising speed. Meaning your fuel time remaining will be inaccurately low, and your ETE Dest inaccurately high.