I basically fly the base at a normal comfortable height. However much throttle is needed to fly the plane hands off, no trim or mix.
On the final turn the throttle is decreased greatly and I let the plane start to decend. Whatevers comfortable for the plane Im flying. Then on final I keep the plane flat and level. I use throttle to control the decent and elevator to maintain near zero pitch. Then when the plane crosses the threshhold I can start my flair or wait until the planes in ground effect until I flair. Again depends on the airplane and wind conditions.

Fun to read the different approaches.

Cheers.