Emulate an Ability Score, 10+ spell level, 1st level is 11, 2nd 12, 3rd is 13, 4th is 14, 5th is 15, etc...
Emulate an Ability Score DC for II 12, 13, etc?
Your effective ability score (appropriate to the class you’re emulating when you try to cast the spell from the scroll) is your Use Magic...