Only use this guide if you really really want the complete set cards.
If you don't care which one you'll get, then this guide is for you.
1) Check the Complete Set Card list, and see that there is available ones for set 5-10 currently.
2) Check your Card list to see which Sets is most complete out of what you have.
3) If there is any one of the sets from 5 to 10 and you already have all the 5*s from that set for example, set 7 and you already have all the 5*s from it. Then congrats you just found an ideal set you can make the gold boxes feel the fury of your Wallet cuz its easier to get 4* and below than 5*s. If not, then skip to step 4.
4) You're here because you don't have complete playsets of 5*s in any of the set 5-10. Attempting to collect Complete Set Cards is now high risk gamble for you depending on how much you're missing, and I wish you godspeed for it is in the house's favor. Proceed to step 5 if you're going to take the high risk gamble.
5) Since you have decided to try it, go ahead and grab the gold boxes, and if you're still missing a few, check which prebuilts have same cards as in that gold box that you're missing still, for example, Feria can be gotten in the prebuilt warriors file for 1500, forcibly making alteil give you Feria for 1500 gran is cheaper than spending other 3450 gran and still missing that third copy of Feria. Exhausted everything? Proceed to step 6.
6) If you're still missing that last 1-3 cards, and they're not 5*s or 4*s? Point card em. It's alot cheaper than dropping other 3450 gran. It's likely that you'll be missing a several or just one 3* like I did. Final Showdown got pointcarded. Hiding not allowed. Proceed to step 7.
7) Email alteil and then congrats wait til after maintenance to enjoy your shiny new Complete Set Cards.