Mosfets have a measure of unpredictability. They are not all controlled in the same range of operation, to turn them On & Off. Some mosfets will not work at the low supply voltage of my simulation.
Furthermore an oscillator that doesn't work at a high supply voltage might start working if you reduce the supply voltage.
The twin-tee components usually have a 2:1 ratio among them, so that a particular frequency becomes the center frequency. Both of its T-shaped branches should carry about the same level of current, and have about the same voltage swings. Suitable figures are a few mA, and about 1 volt. These levels are sufficient to drive the transistor so that it gives the right amount of 'kick' to the circuit at the proper time.