That is an excellent video that emphasizes many insightful aspects. I can only amplify it with some additional knowledge and experience.
To reduce the difficulty in slewing, do your slewing as little as is necessary and in the best possible conditions. If you can see the target or target area out the window, by all means fly the wagon wheel onto the target and ground stabilize near it only using the HUD. That means pretend the wagon wheel is a gunsight and maneuver the airplane so the wheel is on the target or very near it and just press TMS aft. Really you can often get a track simply using the HUD with a quick review of the WPN page prior to launch. But let's assume that you didn't get a track and some minor refinement is needed.
Now you've got a grounded Mav near the target, your Mav FOV is adjusted to narrow if desired, video polarity, crosshair white/blank, and you're going to use the slew control for the first time in the attack. The enemy here is going to be parallax caused by the vectors of motion and view not being aligned. To eliminate this drift, put the TVV on the target. The farther your TVV from the target, the more drift will occur. You should find that slewing a short distance (already grounded near target) with parallax drift minimized (TVV on target) should be easy.