In order to achieve very low SD and ES you need to be very meticulous in your tuning approach. While the Mora is generally an extremely easy gun to tune, "fine" tuning will require some time and work. Currently during testing, I'm seeing 2-3 SD and as much as 14 ES depending on the speed and the pellet I'm shooting. However, for serious practice and competition, I will always return to the AEA 29.5 grain Center Punch pellets at 970-975 fps because that is where I get my best overall results. As a starting point for that tune I know exactly the 2nd reg pressure (100 bar) needs to be and the approximate position for the dwell adjuster (on my gun that's six holes from closed). However, because I'm using a 700mm barrel, your settings will be different(most likely a few bar higher on the reg), if only slightly.
Once I have my gross starting point, in order get my SD and ES minimized I begin bumping (and I do mean barely moving) the regulator and adjusting the dwell, in equally small increments, to offset the direction (increasing/decreasing) that I moved the regulator. What I'm doing is trying to find that extremely small balance point that gives the pellet an initial SLAP (shortest possible burst) of air with NO trailing air. This balancing point can take a while to locate. I requires going back and forth until you hit pay dirt. Now, the question is, is this REALLY necessary? Well, IMO, that depends on what you're doing. For ME, as a benchrest shooter, the answer is yes, because consistency is everything when dealing in millimeters at 50 to 100 yards. Although a 10 fps spread barely registers on my POI, barely isn't good enough. When I'm POA is 3 o'clock the ten ring, 3 millimeters can be the difference of an entire point. For a hunter, or a plinker or a long range shooter who have much larger diameters to their target areas, there's little or no point at all in going through all those machinations. Form should always follow function.