Erik is right. Don't do anything with your Q until you consult with the vendor about this.
That said, I'll comment on a couple things. There naturally is drag in the motions due to the nature of the slip clutches, which do not have manual clamps. How stiff is yours? On mine the motions are stiffer than, for example, a mount with manual clamps, where there is next to zero drag if the clamps are released. I bet the perception of stiffness is more noticeable due to the very light weight of the objects being rotated. But that's the nature of the Questar Standard's design; there has to be some resistance to the motions.
As to the drive motor not successfully tracking, if we assume that the motor is good (I would think that would have been checked before shipping), that suggests that the RA turntable nut needs to be tightened, not loosened. Loosening the turntable nut will reduce the pressure and the static friction at the slip clutch interface, which is not what would be needed. If it's determined that you need to tighten the turntable nut to fix the tracking problem, it probably requires only a small amount of tightening. 1/8 turn can make a big difference in the pressure applied at the clutch. (Adjusting the clutch pressure does not require removing the knob for the RA slow motion.)
The setscrews require a very small size of Bristol spline key. I was mailed two of them by Questar. One of them has a shortened length in order to be able to "squeeze" into the turntable nut's setscrew. (There is reduced clearance between the flats of that nut and the sides of the depression it sits in, requiring a shortened key.) My turntable nut has two setscrews, both of which need to be loosened in order to turn the nut.
The maker of those videos you watched on youtube is indeed a frequent poster here, to our benefit.
Hope this helps.