I wouldn't worry about pulsing a rebuilt Kanger head to remove residual oils and to check for proper heating. Just don't stand on the fire button- all you need to do is get the coil hot enough to give off that tell-tale puff of smoke, and to see the coil is heating from the inside out, w/o any hot legs. In my experience the real damage is done to the insulators by a hot leg, and if you don't dry burn the coil before wicking, you'll never know you have a problem until the atty is built and filled. Again- just my experience, YMMV.
Below is a Kanger head from a Protank 2, wick is almost dry after finishing the tank. It's a NR-R-NR coil so no worries about burned insulators. I rebuilt it using 6T of 32g Kanthal, 1/16" ID, 1.8Ω. Legs are 30g nickel. Good all around conservative build, I run it around 10w, give or take. This is after 55ml of DIY Capella Caramel/Vanilla 40/60 12mg. Not claiming any sort of record here, just don't recall any recent photos of well-used Kanger heads: