Cobra Trailer Wiring Presentation Available for Download

Usually they are called "CHMSL" or "center high mounted stop light" instead of HEP. I guess either can work.

As to hyperflash, it's a byproduct of the low resistance in an LED used in a signal. Typical fix is either a high watt low ohm resistor. Similar happens when you lose a blinker filament, the circuit load drops.
You can find info on the DiodeDynamics install page. DD makes various LED lights.

I have thought about a series of eight LEDs across the top of the dog house.
Four red in the middle connected to brake circuit.
Two amber or yellow on each end tied into the turn signals.
Makes cars further back see what you're doing.