Hi Tim,
here is another version with a transistor, that way you wont have to worry about the VR burning up.
http://www.cbtricks.com/radios/cobra/mods_&_info/graphics/Cobra_Uniden_Var_Pwr.pdf
Also the statement "very similar to what the NPC-RC mod does on ssb & 10 meter radios" not too accurate... it will allow you to lower the key and get "swang", but the radios use different techniques to produce AM, and so the two modifications can only produce similar results to an extent, you won't see the sinusoidal waveform out of a 29 much past 105%, it will start to turn into a triangle waveform, and eventually the envelope looks like a PWM signal or "box car", "loud" but nasty as all get out.. (bye bye adjacent channels)
I'm not dogging on the mod, I've used it; like your paper recommends, a 47 uF capacitor will help to keep it cleaner, a larger cap value would let it over-modulate more. I like to keep the AMC enabled and once you use too large of a cap and lower the key too far, the waveform loses its integrity even if the diode isn't snipped and the VR was turned all the way down.
Sometimes, I just pull the jumper between driver and final, to add an attenuating resistor, reducing the signal from the driver to final, lowering dead key (and max P.E.P.) without mutilating the AMC/Waveform when you modulate the carrier. When I add the resistor I usually have to adjust the AMC VR to compensate. (So it doesn't swang into distortion)
73