Due to the differences in different tanks, there can be no single "best" answer but it needs some adjustment to fit the situation. One big thing is how you control the CO2 and what level of plant growth , etc. you require for your results to please you.
What pleases you will vary as you may have fish that differ from other users and your priorities on which takes first place, fish or plants, may vary. Different fish react to CO2 in differing ways, so if the fish are priority, you may want to run different than plant first folks. Plant first folks may want to totally max the CO2 levels to get the ultimate growth but that can risk the fish so fish first folks may agree to less CO2/ less plant, but more fish safety.
Many turn on the CO2 early as mentioned as they want the plants to have it maxed as the light comes on. This may work well with lights and CO2 on separate timers but it can result in the fish having too much CO2 if the calculations on timing are off a bit.
Some are willing to accept less Co2 at the start of the day but somewhat more simple to let the lights andCO2 be on one timer. Plants suffer lower CO2 and fish suffer slightly higher at the end of the cycle. So it may depend on how close to that max your fish will tolerate and that varies with different fish and tanks.
If you use a controller, you may want it to simply keep the CO2 level steady 24/7 for a stable set for both fish and plants.
Not a simple question and does need some looking at what goes on in your tank. I currently run tanks using all three methods as each tank varies.