Twilight is fine. I haven't flown the Anafi in really dark conditions. mainly because I have found the Spark makes me much less afraid of losing it than the Anafi does.
This is a video I made about flying the Spark in rural winter darkness:-
[MEDIA=youtube]zBHCWbNh1YM[/MEDIA]
When autumn comes around again and my daylight flying opportunities fade I will probably investigate ways to add extra LED lights to the Anafi to make it more visible. I did buy some luminous tape which I added to the Spark, it wasn't a complete disaster. It made it slightly easier to see the drone when it was taking off and (to a lesser extent because they fade fast) landing. The lights on drones work quite well to allow you to see where they are, but seeing which way they are pointed is really hard. That is why I think that pre-flown flight plans would be the way to go. Use a short plan, don't go too far, and don't program the gimbal position with points of interest so you can respond to what you can actually see rather than what you hope you might be able to see.
You can save your flight plans off your phone and put them back again later. This I discovered when I upgraded my phone. You could fly a route in the summer and then save that flight plan on your computer and stick it back in your phone in the darker months. Flying the same short flight plan at different times of day, different seasons and different weather is probably a good idea, just be aware that trees grow...
