To fix this problem you could also do this: Let the info be a hold and for quick slotting, when you are selecting your target, to show on the popup that informs you that you are aiming to add another button on that same popup, a quick slot button. I find it natural and the solution that requires the least amount of taps, too. For inventory effects the button could be next to the inventory text. Instant effects are a bit more complicated, but my idea is that, when used, the quick use icon of the effect you just used would pop up, maybe on a color other than blue, that when touched opens a pop up asking if you wish to assign the spell as a quick slot. If rejected, would dissapear. The other colored icon would remain for only one turn. This icon may too have the least priority of them all, appearing on top of all other quick actions.