Forget the " Speed Ring " as a real reliable referance to preset your speed...
Site in percisely at 20 yards using the main cross hair and a good solid shooting bench.... After getting it " nutts on ", take your target out to 40 yards. Turn your speed dial to aprox 315 fps as your stock quills and 150 gn boltcutters will be very very close to 400 grains, which on my Micro go thru the crono between 315 and 320 fps...
Hold the 40 yd. crosshair, ( the one regulated to 40 yards ) which is the 2nd one below the main one ( the one you first set at 20 yards ) and shoot one arrow... Adjustment can then accurately be made by turning the speed ring up or down to bring POI to the exact aiming point elevation wise, at 40 yards.... If your arrow is high (above the target) turn your speed ring up, to say 325 fps and shoot again... if below the target, turn it down too say 310 and try again....only make these adjustments with the speed ring... DO NOT re-adjust the main crosshairs for elevation changes after setting them for 20 yards...
You may see a slight need for windage adjustment at 40 yards if there is no noticable breeze and thats fine and often necessary... Once your dialed in at 40 yards, tape your speed ring in place if it has no set screw. However, I think your Hawke may have a set screw on the "speed ring" that can be set ( but not too tight)
At this point, your basically done... and only need conformation shots at 30, 50, and possibly 60 yards too confirm.
I hope this was "clearer than mud" so you can see what I was trying to explain and of some help to you.
Gene