Well, according to this, I didn't open enough boxes this event but this is what I did so far:
T-bars 7 all cash.
Docs 10 mostly cash and 150ish gold could have been 165. Opened about 90 boxes
Plane parts 9 all cash but 45 gold.
Nukes 9 cash and about 180 gold.
Vaccines 8 so far using combo cash and about 480 gold holding out for full tilt gold t'il tomorrow!:
that was with 36 hrs remaining so add another 32 boxes with some resets and I spent a total of 960 gold to get to 9. That's NIC the 2.5 mil on cash attempts