Sweet spotting the regulator is not a quick process, but it is easy at least, and integral to an Autococker running at its most efficient.  It is time consuming, and requires a good deal of air, and some paint.  You also need a chronograph (those handheld radar chronographs are great for this)

   The relationship between an Autococker's input pressure and velocity is in the shape of a bell curve.  This means that as pressure goes up, so does velocity, but only to a point.  There is a point where any more input pressure results in a lower velocity.  This is because the excess pressure is causing the valve to shut prematurely, stifling velocity. 

   Start by turning your inline regulator all the way down to zero psi, also set your velocity adjuster at two turns in from all the way out.  Now, increase your pressure slowly while shooting the marker over the chronograph.  Adjust your pressure 25 psi at a time, and take five shots (give or take) over the chronograph to establish a velocity at that pressure.  Continue this process until the velocity peaks, which is when any increase in pressure will result in a decrease of velocity.  This point varies for every marker and is the most efficient pressure setting for your spring set.  When the velocity drops, start lowering the pressure (5 psi at a time).  The velocity should start to go up again.  Gently nudge the pressure lower and lower (using those small increments) until any change, be it up or down, results in a lower velocity.

   Now that the regulator is sweet spotted, you need to adjust the velocity adjuster to reach your desired velocity.  With any luck, the regulator will sweet spot right around 290 fps.  Try not to turn the velocity adjuster in more than half way, as it tends to put too much stress on the spring.