I´m an electrician Jim, i just use my side cutting pliers.
It´s all in the feel, one can easily tell when the insulation yields, and is ready to be pulled off there.
For these thin cords i admittedly downgrade to a small electronics side cutter, as i can hardly see the plasmaball behind my usual one.
This is the exact model i use:
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On a different note, but within the same brand, i highly recommend a Bahco 4430 for our hobby here:
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I find it downright amazing when working on thin sheetmetal, like straightening old fireboxes, or making a new set of boilerbands.
It has smooth jaws, with a relatively low grip, but does not leave any marks at all on the surface, and is so small (5 1/4" total) that it can nearly fit anywhere.