Well here’s my thoughts on the matter.
I play the premium slot and will continue until i have SS equipment on all birds, i got only red left (has an S offhand).
After that i’ll save gems for exclusive slot. Think 30 gems is enough. Now it’s important to keep one thing in mind (it’s what i keep advising but rarely anyone tries it), to beat computer generated randomness, you must fight back with your own randomness, or else you have very lower chances to pull something good, click after click (to pull) is not the answer, used a random auto clicker for many games and i must say that i always gotten better pulls than most (my last premium pull had 3 SS items, got the special ship part, whohoo). What i mean basically is that between pulls it’s much better to wait a certain random amount of time, that’s what got me better items more often. I use teamviewer quick support coupled with a custom (made by me, don’t trust random auto clickers from the net that much) random auto clicker. You got nothing to lose if you try, just remember, it doesn’t guarantee good pulls all the time, so you have to use it multiple times in order to see the difference. Hope you get good pulls…and gonna cut it here, already a too long reply. :-)
Oh and, doesn’t matter much to me what others say, i have used this method for a long time (read years and years) and it works.