Yes, I completely agree with Keith - although he recommends a factor of 10*Q (my recommendation was only 2*Q...3*Q as a minimum). I doubt if there is an "exact formula" for this purpose.
However, perhaps you can try to speed-up this process by using something like a "kick-start". This was proposed in an "Idea for Design" contribution in Electronic Design, October 24th, 1996, page 86. This starting aid consists of a damped sinusoidal waveform which fades away with time and leaves the oscillator "alone".
This signal should have the expected frequency - as exact as possible.
If it is a voltage, it has to be connectet to a node which is normally grounded.
If you choose a current source it can be feeded into each node.
Good luck.