Notes & Combos
The gems there is a lie, you can get a full run through the rush selection box with gems, this only lasts until the box is gone, but for now this is by far the best you can do with your gems.
You can build the whole deck using 1 run through the selection box (4800 gems with worst possible luck), then use 1 UR and 1 SR dream ticket for the 2nd magician and 3rd witch. It's very likely you'll get the sorcerer from the free packs that come with buffered slime and negate attack deals. total price being less than 7k gems, and around 8k with the absolute worst possible luck.
There's room for changes if you want to go deeper, but this is what I hit KOG for the first time with. If you have 2-3 sorcerers, yolo them in, a second Torna would also go well, you'd likely replace the Rising Light Angels with them if you did, they are disgusting when you get them on first turn going second, but otherwise they're nothing special.
Replays
https://duellinks.konami.net/att/0242eac5037124a7d37bf911bf693b049cd807a6b7
https://duellinks.konami.net/att/03d3811848f39d311014107dcf65b2dc76f718fc4a