Prototyped, works well. Q1 is a bc945 connected directly to 555 output at 0-5V. Q2 is a bc337. when it turns off, EMF in the coil is jammed between D1 (uf1007) and Q2 but clamped to 12V. this puts the gate at 12V which is ample to fully on the circuit.
frequency and duty cycle can be adjusted up and down, but high pulses longer than about 10μ sec started to ring down.
