Well, most decks are built to be the 30 card minimum, and the number of quanta generating cards (be it pillars, pends, novas or immos) is usually around 10 in total. I would suggest doing a simulation of draws in game 10 times (or using the game simulator). With this card, there will be no redraw issued in the event that none of the starting cards are spires, so using 10 specific cards (such as 5 vampires and 5 pests in a deck that cant use them so they stick out) without any pillars/towers/pends, to simulate spires.
honestly though, my goal was to come up with a card that would reduce the number of quanta producers you need for an effective deck, while having the two aforementioned drawbacks to balance it. i dont think the current card design hits the mark, as it is too slow early for it to be competitive with traditional means, in the event that it does show up in your hand early.
another possible limitation is using the 6 card max, similar to SN, which also is exempt from the mulligan rule.