Does anyone know what vacuum NC 24 carbs should be running?

I can't afford a set of gauges so I'm going to make a set (my dad is in the precision instruments trade). I just need to know what range gauges to get.

Most of the gauges I've seen online have a range of 0.0 to -0.6 bar.

My gauges for a NC30 are 0 to -100kPa, but to avoid bad flutter the needle only gets to around -20kPa, so get something 0 to -40 for decent resolution