The main reason you want to short shift and not rev to the redline is because in the lower gears, a considerable percentage of the vehicles total kinetic energy is in the engine’s rotating momentum.
When I was in college, I calculated the percentage of total kinetic energy the engine’s flywheel had in each gear of a Harley Sportster basing it on the engine having a 28 pound crankshaft that had an overall diameter of 8 inches.
In first gear, it was something like 35% of the vehicle’s total kinetic energy was tied up in the kinetic energy of the rotating crankshaft. In fifth gear, it was only around 10 or 15% of the vehicle’s total kinetic energy, based on memory, I lost the exact numbers long ago and it was theoretical anyway based on an estimated flywheel rotating mass and an assumed rider mass.
So the less flywheel the engine has, the less the penalty for not short shifting will be and the more efficiently the vehicle will accelerate.
You might consider buying an “underdrive” alternator pulley at the speed shop, there’s a lot of rotating mass in the typical alternator especially when you consider it spins two to three times the rpm of the engine.
With a step less CVT transmission, the engine rpm is steady as you accelerate so you don’t waste energy accelerating the engine over and over again in each gear plus the kinetic energy of a highly revving engine can be recovered by the transmission gradually upshifting to an overdrive ratio at the end of the acceleration.
In my attempts to get better than average gas mileage, I have found very little mpg gain by accelerating ultra slowly, in fact, I find it can actually worsen my gas mileage. The kinetic energy of a car going 60 mph is exactly the same whether you accelerated to 60 in four seconds or whether you took all day to get there. You might as well give the car that energy at the engine’s peak specific brake fuel consumption point, within reason of course. If your engine is so powerful that this results in wheelspin, naturally that’s inefficient.