This is the relevant page from the big document I linked you in another thread:
With thanks to Cadfael.
In both schematic and wiring diagram form, it can't be made any simpler than this in my opinion. Also, why are you using 250k pots and expecting the same results? You have fundamentally changed something about the circuit by using 250k pots instead of 2.5k. I'm not surprised it's on/off - the zero point is fine but you hit 2.5k very quickly on the sweep of the 250k pot and anything beyond 2.5k will result in no change to the output of the circuit. That's why you're experiencing on/off type results. Once the pot hits 2.5k resistance, the other 247.5k of resistance isn't going to block the signal harder, after 2.5k it's just blocked from going to ground/through the tone circuit. Only a hundredth of the pot's total sweep is going to have any effect. That's why it's on/off.