The reasonable value for center of gravity compared to the center of lift is a 2 part process in horizontal stabilizer design. Set static stability aside for now. For most efficient flight you want the main wing only generating lift. Ideally, the horizontal stabilizer should be at 0 AOA, holding the wing in place at optimal Lift/Drag AOA. Center of gravity is directly under Center of Lift.
Job 1 complete.
Now we want to introduce static stability, also known as speed stability. This is extremely important when you are "low and slow" to avoid stalling. It is a terrific safety feature even with computer assisted control. So you move your TRIM tab to give a little bit of tail downforce and move your CG slightly forward as needed for adequate static stability. Job 2 done.
The 3rd function of the horizontal stabilizer is to pitch the nose down if the plane sinks, in order to avoid ever increasing AOA and unrecoverable "deep stall". Here, within reasonable limits, the more area, the better. Wedge or delta shaped designs are popular with birds.
So there is a difference between a horizontal stabilizer and a trim tab. Champions of tiny
Hstabs should be aware of this (although a longer fuselage does also increase pitching torque).