Pertronix question (Ignition on 'safe-guard'?)

[KevinK7]

I recently installed a Pertonix Ignitor and Flamethrower II coil on my 68 C20 (396). Since I'm still doing work on the truck, I haven't yet attempted to restart it, but I have a question about IGN on and the vehicle not running. I realize this can/will overheat/damage the coil since with the Pertronix recommended hookup, 12V is wired directly to the Coil+ (ie bypassing the factory resistance wire).
Obviously being aware of this, I won't intentionally leave IGN on for any length of time while vehicle is not running, but has anyone implemented any sort of 'safe-guard' to protect ...in the event the key is inadvertently left in IGN when not running?

By "safe-guard" I'm thinking a fuse, ..switch, timer, something that will prevent 'runaway current' that eventually kills the coil and whatever else is in it's path.


Thanks,

Kevin

For reference, this is how I have my Pertronix wired: