Thanks for the confirmation, Bruno!
My calculations above are already with the swapped gears. I was basically just confused whether the "green gears" or the other alternative with all 16 gears is the "faster" one.
Regarding the battery box: I am using the Mould King battery Box with motor driver chips exchanged for something more solid (RZ7889 chips). The big advantage is, that with the Mould King battery box you can simultaneously control up to three channel. So I have 2 L Motors each on Channel A and B and can operate them all together just with the A buttons. That is quite convenient. And the driver chips are also quite powerful. Nowhere near the BuWizz of course, but at least way better than the CaDa battery box, which fails completely in driving this setup. And way cheaper as well.
The CaDa L motors are really impressive. They are really strong and with quite low amperage need for the torque they deliver.
I have built the complete drivetrain, so up to roughly step C100. In this setup, the 1 Mould King Box is driving the model quite well in all gears. I will now continue with the build. Let's see what the added weight of all the red parts now does to the performance!