How much ER% does Augusta need to Mini-burst every rotation? And what is the optimal rotation?

I tried looking up videos and i'm not gonna lie, the standard rotations only work for first rotation for me... for the second and subsequent rotations, i'm not getting her Mini-Ult fast, so i end up doing the forte fill-up+Heavy attack extra times and a lot of times, Mortefi's buffs run out by the time i get Big Ult.

My Augusta has 120% ER... I've seen a lot of CCs do rotations with Lower ER than mine and yet i'm not getting her Mini-Ult despite having similar or a tiny bit more ER%.

I saw Gacha Smack's video on a different rotation and i ain't gon' lie, i actually love that rotation a lot... it alteast gives me the Big Ult immediately and then i build up the small Ult later. But i saw someone in comments section say, that rotation loses the crown buff on her Mini Ult...

So what is the actual absolute optimal rotation for Augusta? And how much ER% is wanted for said optimal rotation?