Power spell confusion/frusturation

I have a few questions about power spells

  1. Is there a specific upgrade level where different rewards start to appear or are all rewards avaliable from the start and just generally harder to get the less you put in?
  2. What are the chances of getting special cores? A while ago I got 2 cores for the master shapeshifter and have since then never got another core for any creature did an update remove the ability to get cores from spells?
  3. Do common rewards change at all with the more you put in, as in 5000 could get you 5 pandemonium tokens and one exalted while 20000 may give you 10 and 5 respectively or is it all just a gamble and hope you get better rewards at the cost of more power?
    Honestly I just want 2 answered I really want that last core and it’s driving me nuts not knowing if I’m doing something wrong or if there’s a simpler way to get it than powerspells.

1: I’m pretty sure all Power Spell rewards are equally (un)likely from the start, with one minor caveat below

2: Your very first Power Spell will always award three cores of one of the Power Spell creatures (mine was the Incursion Reaper, but there’s like half-a-dozen others). After that it’s a toss up between Spell Scrolls, Tokens and Emblems, Major Sigils, a few high-grade Shards, a bottled critter that gives instant Power Balance, and one, two, or rarely three cores from one of the creatures. There might also be other possibilities that I forgot.

3: Putting more Power into the Spell increases the chance that it will give you more stuff, but it’s not a guarantee. I’ve had 25000 Power Spells give me anywhere from one to four Major Sigils at a time, but if you don’t put forth the extra effort then there’s no chance for extra loot.
Just make sure you’re not spending more Power on the things than you’re gathering while charging them.

Higher amounts of Power invested will unlock different categories of rewards, yes.

Power Spell Cores are rare even at the maximum investment level, and are almost impossible to get at 5000.

More Power investment increases both quality and quantity of the rewards, but you may also want to consider that you can do 5 5k spells and get much more basic loot than you would with a 25k gamble. 5k power spells are by far the best way to get Emblems, early game, so don’t be afraid to spam them until you get what you want from Bynine (like Nightwing, Clairvoyant, the Crown of Haste, or maybe a class change).

Great, thanks for the replies, looks like my next task is to get that 25k power spell upgrade and try it out a few times