This is one of the most frustrating things in the game. How many times you see endless string of 10. Or you need only 10 to unlock some creature and now you got more than 50.
We see that by averege fuse is ~22-23 DNA, but statistic works for large numbers. So when you develop some rare or epic creatures then it is not so important how single fuse goes. You need lot of them and components are easily reachable. But for legendaries and uniques there is diffrent story. Each fuse need days/weeks of hunting (e.g. 3000k Velo for indoraptor).
Let basic fuse give 25 DNA.
It is close to current averege.
It will guarantee unlocking of unique in 10 fuses, legendary in 8, epic in 6, rare in 4.
Like above leveling creature will be counted in number of fuses.
But there is more. If we got exact 25 DNA from fuse, then we could make partial fuses (and everything divieds nicely). You need 1 DNA of Indoraptor? Then you need 2000/25=80 DNA of Velo and 50/25=2 DNA of Indominus Rex (for which you need 2500/25=40 DNA of Velo and 250/25=4 DNA of T-Rex, so you need 120 Velo and 4 T-Rex).
Furthermore fuses could be any amount, e.g. if new hybrid is in the game then if you got DNA then you should be able to unlock it in one click. E.g. new legendary from two rares need 8 fuses for 200 DNA each, so if you got 1600 DNA of both components then in one click you unlock it.
Now making grypholith require 20 lvl of purrolyth (and 500 DNA for fuse), currently it’s a hours of clicking fuse button.