Although the only card that can traditionally be sacrificed is Solemn Simulacrum , Ashad gives your nonlegendary artifact spells casualty two, which means they can be copied by sacrificing a creature(s) with two or more power
(Equipment, Auras you control, and counters are modifications.) Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.) Once Obstinate Gargoyle has been blocked, causing it to gain flying by modifying it won't cause it to stop being blocked
You can ideally get two or three cards off the top of your deck, assuming you dont hit multiple lands, and you could even use explore to manipulate this a bit
You must follow the normal timing permissions and restrictions for the target artifact card
If any cards have the End of your turn keyword, you may activate them after your Main Phase