@Dorijan-Lendvaj is having some technical issues right now so I'm helping him put his work online. All credits to him, I just did some basic copy pasting!

So, I made the best strategies for spending gems if you want to reach a certain node. First, I'll explain how this works:

-For each monster, there are several possible strategies with various amounts of time necessary. I'm also putting some strategies that take longer to complete than the island lasts because, if an island boost happens, the items take 2 times less time to collect, meaning you get twice as many items during those 2 days, which means you effectively get 4 days worth of items in that time, which can also be translated to 2 extra days. Note that recently island boosts became less common so scroll

-To find the strategy that suits you, think about how many times will you collect an entire pool of items in the 10 days of the island, and multiply that number with 8 hours to get the amount of total time you want on your strategy. Note that if the number of hours is divisible by 8 on all collections, I put the number of collections as a reference and not the number of hours.

-I'm considering the amount of time required to get items once they are in the pool as 0.

-How the strategy works: For each quest, the strategy tells you the number of gems to spend on that quest. Note that quests which only require 1 breeding item can be completed almost instantly so they aren't included.

It also says after how much time is required to get you to this gem cost if there is no island boost(or if the number of hours is divisible with 8, then the number of collections), which is mainly helpful if you divide it by 8 hours to see how many times you should collect the entire pool of items after you get your first collection. Note that dividing by 8 also works if you're planning for an island boost; just make sure to collect every 4 hours instead of every 8 hours.

If you're going by every hour collection, you might see a remainder when dividing by 8(usually 4, when you get 3 gold and 2 food items without waste); that means that it's optimal to collect an incomplete pool and then gem.

-If you have any other questions, feel free to reply on this thread.

I'll add more as I create them.

For collections every 8 hours:

Rank 5 Itzanami: /pastebin.com/kuCt7YhQ

Rank 4 Itzanami: /pastebin.com/yf42w9j4

Rank 3 Itzanami: /pastebin.com/YcJX4wVU

Rank 2 Itzanami: /pastebin.com/0L9kT66n

Rank 1 Itzanami: /pastebin.com/qBEdPWw6

Rank 0 Itzanami: /pastebin.com/ZFdUSe9m

Talika: /pastebin.com/FxywHNs2

Mountezuma: /pastebin.com/JfHNj5b0

Tempest (can get with 0 gems): /pastebin.com/K6zb0m2c

For collections every hour:

Rank 5 Itzanami: /pastebin.com/41TqcXrN

Rank 4 Itzanami: /pastebin.com/bNWqg8zS

Rank 3 Itzanami: /pastebin.com/CySjWUD2

Rank 2 Itzanami: /pastebin.com/rQHFCV7b

Rank 1 Itzanami: /pastebin.com/LAQzCEGD

Rank 0 Itzanami: /pastebin.com/BAEtaHA1

Talika: /pastebin.com/gPwZbpMj

Mountezuma: /pastebin.com/iG50YUtd

Tempest (can get with 0 gems): /pastebin.com/t7EM6x5M