In a CA climate (assuming you don't live at 8000' of altitude) it's fine to just let drip onto the roof. The amount of condensate (or melted defrost) you get will vary by the actual outdoor temperature & humidity. I have relatives in the foggy-dew Puget Sound region of WA that probably get several times the amount of condensate/remelt that you would anywhere in CA (due to the lower outdoor temp & higher humidity, and the higher/longer heating duty cycles) who just let it drip onto the ground next to the foundation without need to re-direct it.
You'll still get frost on the coils in CA, usually starting when the outdoor temps are in the mid-40s, but defrost cycles are brief & efficient. You get more frost + remelt when it's 40F and foggy than when it's 25F and sunny, due to the dramatically higher moisture content of the air under the warmer but wetter air condition. Any time the coil temp is 10F lower than the outdoor dew point and the duty cycle on the unit is high the condensation/frost rates pick up. Most of the time in heating mode the coil temp will be more than 10F cooler than the outdoor temp, for efficient heat exchange across the coil. Both the compressor speed and blower speed are continuously variable, and controlled to deliver the required amount of heat with maximum efficiency (the algorithms for the controls are proprietary to the manufacturer.) Efficiency is pretty high when it's condensing & frosting, despite having to periodically defrost, since the both the heat of vaporization & heat of fusion of the water is gained by the coil, and only part of the heat of fusion is given back (to get the frost to release and get blown out by the fan.)