I finished my base set on the 4th box as well, so 8 boxes total to get the base set, the 4th box, had all the base set I was missing, so I'm assuming you get a certain part of the set from each box.
I was a little annoyed at this, because ALL the standard refractors I got from the 4th box I also already had, literally every single one (apart from blues/gold).
Box 6! the first mini box I opened was a major letdown until the Tate auto came! everything else until that last pack was bad compared to other boxes. Still haven't really seen a "case hit" I would suggest yet, 2 more boxes to go opening tonight, let's see what we get
I'm still really enjoying collecting this set, after opening this case, it will be 12 master boxes total I've opened, from this I've obtained roughly just over half the Refractor set (base only, haven't gone through all the /8, /88, /188, with those would probably have close to a full set for sure). Also majority of the 2 other insert sets, the Valor and Finest Moments.