I had the same idea, and posted here a while back about changing the knobs on my NG2 to the Canadian knobs. As suggested, I contacted Jason at Fret Nation, who told me the 6mm knobs were the right fit for the NG and Combustion models. I ordered five of them since the Dingwall store remains sold out, and they came last week while I was on vacation. Turns out the volume and tone control pots on my NG2 use the 6mm knobs, but the pickup selector switch has a fatter shaft that requires a 1/4" knob. Emailed Jason and he's sending me one 1/4" knob with a label to return the other one, so it's all good, but now I understand why Dingwall sells the 5 knob sets with shims to accommodate both 6mm and 1/4" pots.
And the stock knobs have a set screw, as do the replacements.
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