Sharpening Settings vs. Number of Devices in Capture Chain
 

In general, should sharpening be increased to compensate of the softness added by a TBC or other piece of equipment added to a capture chain or should default settings be left as-is?

Using AG1980s with sharpening set to the middle.

Sharpeners are best applied during post-processing. Oversharpening artifacts caused by the initial sharpener won't be undone by softening or blurring of a later component. Adjust your component settings to fit the specific situation and signal source. There is no one-setting-fits-all solution for every capture situation.

The AG-1980 middle-click sharpen position doesn't add extra sharpening on its own. It is a neutral setting.

Sharpening during capture will sharpen noise. Is well sharpened, overly visible, and more obvious noise the effect you want during capture?

I certainly don't want noise sharpened, but this gives me the impression that hardware sharpening is almost always bad, which I can understand.

What would be a case, if any, where you would increase sharpening at the VCR level?

I guess such a case would be possible, but I can't think of one where I would use sharpening during capture. You can't do it without sharpening undesirable factors. If anything I once had to slightly reduce the VCR's sharpening for a tape that was mastered with oversharpening effects to begin with (apparently some very primitive early "digital enhancements" by the production lab. Phooey, it looked terrible). But frankly I found that recapturing without that reduction allowed me to resolve the problems later with Avisynth filters.