I am afraid Sakura Gift event is not suitable for F2Ps my friend.

First off, the event is a competition based on the whole Region. There are a lot of whales who are always active in that event. They are willing to go beyond rebates just to get the top Rank since the reward is Superb :)

F2Ps should avoid Sakura's Gift event if your main goal is to get to the top rankings. You have better chances of hitting top ranking in Ino's flower if you really want a ninja since it is non-cross server competition. But that would also require a lot of patience and potion grinding.

If you are asking for the amount to hit 1000 friendliness, that I can't help you with. It's also RNG meaning rough estimation only. Hope this helps!