Crackling distortion

Your cartridge isn't properly aligned. I had the same symptoms until I figured out how to correct that.
Good advice above..
The first thing I needed to do was set the proper overhang using a protractor or gauge. By definition, the overhang is the distance between the needle and the center of the spindle while the needle is in a straight line through the spindle to the pivot at the rear of the tonearm. So you have to get down and sight it like you're aiming a rifle.
Next, the VTA. The face of my cartridge is 90 degrees to the top, so if I can get the face of the cartridge square to the platter, the arm and cartridge will be level with the platter. I used a block of wood (similar to dice) to check for square as I adjusted the height of the tonearm. My tonearm lacks any way to measure the height, so I used playing cards as shims to gauge the height at the rear as I checked the face of the cartridge with the wooden block. After I got things level, I checked and adjusted the azimuth using the square block against the left and right sides of the cartridge body till they were perpendicular to the platter. Finally, I used a tracking angle gauge to verify the cartridge alignment.
Since any one thing can affect another, after I was done, I rechecked everything until I had everything zeroed in.
Now the cartridge was flying straight and true.
Since tracking force can affect VTA, I did all of these things with the tracking force set to the cartridge's recommended tracking force on a non spinning platter with a normal thickness record on top. To keep the record and stylus from damaging each other, I covered the record with a piece of glossy, photo weight paper. The glossy paper allowed the cartridge to drift back and forth over the surface without damaging either the stylus or record.
The last thing I did was set the antiskate using a test record till the test tones played with the least amount of distortion.
Now finally the tone of the music is correct (VTA and Azimuth affect tone) and the record plays to the end of the loudest tracks without distortion.

Yes, that also works, since like you said you are compensating for the additional height of the Digital Scale with your VTA.  I have also done it that way in the past.  I, however, don't do it that way anymore, because I find it difficult to compensate exactly with the VTA, it is really eye balling it.  The purpose for 2, is you don't have to make the VTA adjustments, because the platform of your digital scale will be exactly the height of the record.  when you look across the record, from the other side, then you should see the stylus resting on the Digital Scale platform, just like it was on the record.  That is when you know it is perfect.  I believe you can be much more accurate that way, then adjusting VTA to compensate, because it is a little more imprecise trying to eyeball that

The geometry of the dynavector 20X2L looks very similar to my Grado Sonata1. I don't understand how your method square's the thing up to the record surface. Eyeballing the face and sides of the cartridge till they were flush with the square block was rather simple. Adding or removing a playing card shim was a simple way to listen and adjust.

Captain . . . I appreciate that setting AS force will depend on all the other variables mentioned in your post. Just curious how you decided that "[o]ne donut at the top of the vertical bar, with the fishing line on the top, and no donuts on the horizontal bar" was the amount of AS forced needed.

I just guessed on my rig. Two donuts on the verticle bar to hold the looped fishing wire, and one donut on the horizontal bar. I think we're pretty close because the verticle and horizontal bars will offset each other.

Thanks

I use the Ultimate Analogue test lp Side 2, Track 1 Anti-skating test; 315Hz amplitude sweep to +12dbu (Lateral) the sweep begins clean in both channels. Without anti skate as the sweep increases DB the right channel distorts first. I increase anti skate until both channels distort at the same time. I noticed that this is very cartridge Dependent. My current cartridge requires no donuts on the horizontal bar, my other required 2 donuts. Begin with no donuts and the vertical donut at the highest level. If the right channel distorts first, lower the fishing line and top donut. Keep going all the way to the bottom, if the right channel is still distorting first then add a donut to the horizontal bar, and begin again. BTW, about half way through the sweep you will start hearing the right or left channel distort. If you have too much anti skate the left channel will distort first, then you back off the anti skate. I do everything else first, alignment, VTF, VTA, AZIMUTH, all of it. Then I do the sweep test and adjust the VPI mechanical anti skate until both channels start distorting at the same time. It is very precise, too much and the left channel distorts first. Too little and the right channel distorts first.
I admit this is optimized only for the one part of the record which has the sweep.