I've been watching a lot of OSRS streams lately, and many of them use prayer flicking in order to pretty much fight everything. Prayer flicking allows them to not lose any prayer points or to lose them extremely slow, while not taking any damage since their prayer protects them. From what I understand, they are able to do this because of how the game uses a game tick. You turn the prayer on and off very fast in order to not lose any prayer points and absorb any damage.
In Runescape 3 (the modern version of the game), prayer points drain much faster, but you have more of them. However, you only lose prayer points every game tick, just like in OSRS. When I am fighting more difficult creatures, I still take hits from them that are above 50% their max hits (I use the deflective curses, which reduces damage of the curse type by 50%), meaning that I am not getting my prayer flicks correct.
At what time do I need to turn my prayer on and off by in order to reap its benefit while also not losing any prayer points (or as little as possible)? Is it the tick before the creature does damage to me or the same tick as the time the damage is dealt?