As to the secret rares, my guess is they are printed on the holo sheet, each appearing 4 times on the sheet, which would give them an actual rarity of almost 1 per box: (4 x 3 / 121) * 10 / 36 = 1 in 36.3 packs
The reality is that with the buff actually being +1/-1, it's a lot less exciting
Just a whole lot of purple, suspiciously arranged flashing Tesla coils, a bunch of mind-controlled creeps and an obnoxious grunt called Murray who, once I talk to him, wont let me leave without a battle
What Are Pokemon TCGs Formats
With everything left over, Ill just throw a few cards into someones order if they buy something (always try and make it interesting, so a couple of cards with nice artwork/not just energies and trainers)