Final Quat Minibrot

Created using Ultra Fractal.
I finally got what I wanted so this goes in the Fractal Art category instead of my scraps.
The image is just about exactly what I was aiming for, the bonus is that the time has come down to just 3mins 12secs for exactly the same render at 2048*1536 (the original time was 50 mins, then 19, then 9 and now just over 3).