Adjusting Tracking Force and Antiskating
Too light or too heavy?
— What damages records more, too much or not enough downforce?
— Setting the downforce too low, without any doubt.

Setting the downforce (slightly) higher than recommended doesn't damage the records. It doesn't sound good, and your cartridge might "bottom out" on warps, but unless you added more than 10 gram, your records would be fine.

The opposite is not true. Not enough downforce causes the stylus to mistrack. Mistracking throws the stylus around violently, irreparably damaging the vinyl grooves. Even half a gram too little is often enough to ruin your valuable record forever.
— My cartridge's manual shows a range for tracking force. Shall I set up at the lower or the higher end of the range?
— Always start with the higher end of the range. Unless you live in the tropics and have no air conditioner.

The cartridge manufacturers give a range of recommended downforce (say, 1.8-2.0g) because the elastomer that holds the cantilever changes its stiffness with temperature and humidity. The colder and drier the air is, the stiffer it will be and the more downforce would be needed to ensure distortion-free playback.
— How much tracking force is too much? Does 3-4g downforce ruin the records? Isn't 1 g or less better?
— Anything up to 5 gram is certainly fine and does not damage records. In my collection, I have LP records that were repeatedly played back with 15 gram downforce (but always with a good stylus!) They are basically pristine, there is no degradation whatsoever.

The whole idea of "high downforce damaging records" comes perhaps from ceramic cartridges with sapphire styli. Those wore down very quicky (50-100 sides), and the users seldom realized they are already damaging their records. The diamond styli of magnetic pickups got associated with less downforce and, of course, less damage from the hard-wearing diamond stylus.

Very low tracking forces (1g or less) require essentially perfect bearings in the tonearm. A tiny little bit of stiction, and your records would be damaged by mistracking. I would not even attempt running a cartridge with such a low downforce in anything other than a freshly serviced unipivot tonearm.
— How critical is antiskating? How do I set it up correctly?
— Antiskating is a curious thing. Its presence is usually a lot more important than its exact extent.

I would not go into the antiskating theory here. Basically, if the arm has an offset angle, skating force will be present and antiskating should be applied. The offset angle and the stylus drag are the only factors that determine the skating force.

The higher your cartridge's compliance, the more important antiskating becomes. In my personal experience, with the cartridge compliance lower than 5*10E-16 cu, antiskating doesn't really add anything. Between 5 and 10, it's optional. Above 10*10E-16 cu, it's a must.

To test the correctness of your antiskating setting, listen to a real mono LP in headphones. The sound should be exactly in the middle and not "stick" to one of the earcups.

Most quality tonearms have an antiskating scale. Setting it to the mark corresponding to the downforce or slightly higher is a good start. If this gives an acceptable result, you can leave it there.

For a more precise setting, tools are needed. Because the stylus drag is a key factor in creating the skating force, the blank grooveless disc is definitely not the right one to set the antiskating. This is where the test LP comes handy.