I'm not sure where I have heard that is about a minute of casting time but I'm looking for some evidence to prove that statement.
Where it was said the casting time of super tier magic and how much it is?
Also, in the case isn't much (like a minute). Spoiler alert Anime 3rd season cap 12:
Why does Ainz Ooal Gown used a cash item to instantly speed up the casting time of the Iä Shub-Niggurath super tier magic if no one would attack him?
No one on the new world knows what is super tier magic, nor they have the necessary strength to stop him. So why he sacrificed a cash item that he would never recover just to cast it faster?
If he had fear that the enemy could attack him, he could use his army to buy some (a lot) of time.
PD: I don't mind if you spoil me with anime, manga, web novel, light novel, databook, etc. I just want the answer.