You can't pay more energy counters than you have
The only cards banned currently are the Khans of Tarkir fetchlands, but Aaron Forsythe has said that Wizards intends to ban cards aggressively in these opening months of the format
For each odd result you get to create a 1/1 Clown Robot creature token, and for each even result you get to put a +1/+1 counter on Clown Car
Play the usual TeraZard line, evolve to put 2 Fire on Active and 1 on a backup Mander, take some knockouts, then before the first TeraZard gets KO'd (or if you have other ways to keep 4 energy in play, which Zard/Pidgeot should be able to do), evolve to a MegaZard and take out any opposing megas by dealing 380 damage
Seeing these other options, you might now understand why I made the tutoring of Flamekin Herald so central a tenet, as it truly is the best option for doing this