Has anyone tried doing this before?
One potential benefit I can see is that you can easily determine when plants will finish outside at your latitude. It’s hard to know exactly when some plants will start to flower – it’s not exactly at 12/12. Especially with “semi-autoflowering” plants, you might find varieties that will start flowering earlier in the season, like when daylight is 14 hours. It would be hard to determine when plants actually start flowering without a proper simulated # hours per day, and hard to identify the so called semi-autoflowering trait.
Using a real light cycle targeted for a specific latitude, you would be tracking sun hours in your indoor environment. Therefore, you would know pretty accurately which plants will likely finish by first frost.
One downside is that you don’t know exactly when your plants will start flowering. So you might end up vegging excessively if you don’t start from a reasonable date.