Skill books 5vs1(five times)

Hello,
im trying to level Golden Usopp special to max and i was wondering whats the best way. Is it better to give him the book everytime you drop or to farm 5 books and give them all together?
Ty!

I guess my question is on the same sort of topic:

If I feed them 5 skillbooks at one time, do I have a chance of raising the special level more than 1?

i.e. start with special level 1 then jump to special level 3 after feeding 5 skillbooks in one instance.

I sometimes get multiple skill ups when feeding the same characters . Can someone else here confirm that's also the case when using skill books?

Yes, I heard they say 15% increase every skill books. So I think 4 skills book at a time gives 60% chance. or 5 books gives 75% chance. It's up to you if you want to try 15% or 75% chance. For me I rather use at least 2 books at a time. 15% is too low.

Hmm that means that you can get only one skill lvl up with 5 books? I have heard that you can get more lvl up´s when you use more books. I also read in the blog that they assume the drop rate would only double when you use 5 skillbooks and not only 1.

I saw a video where a japanese player always fused 4 books/same characters. Maybe thats the most efficient way?

I already had 10 books for usopp and the level didn't go up once -.-

All the games I've played with system similar to this one follow the same guidelines. Each book/ mob has the same chance of skillup. Let's say that number is 15% chance. If you feed 1 mob, you have a 15% chance if skillup. If you feed 2 mobs. You have a 15% chance on each mob NOT a 30% chance. People feed multiple mobs at the same time to hope the RNG gives them multiple skillups. Now with the next event announced and having 2x skillup rates as part of the event, your best and smartest decision is to wait, holding onto the skillup books/mobs and feeding during that time. If the base chance us 15%, 2x would be 30%. Much better odds and chance of skillups. In other games, PAD specifically, I cAn remember going 5/12 skillups and 5/39(damn valk). It all depends on The RNG and kick.

Luck not kick