With pan matrix, you could do an easy test strip with the red filter. You processed it and then slapped it onto a white tray to judge density. Because the emulsion carried tone, you could make a pretty good assessment of exposure for another test in 3 color that you would print. This same exposure test wasn't required with chromes because your chromes had so little exposure latitude.

H-burgers, you mention fogged highlights.This was an issue that was solved with a solution of Calgon water softener in the first rinse when printing. This made a huge difference in highlights and was (for most commercial labs) a default correction.

Exposing through the base + exposing sep negs through masks + stacking assorted post masks on the negs + making multiple incremental exposures with a register carrier -- all these things effected sharpness.

This is why point source lights were used with long focal length lenses (a 105 apo-nikkor was the industry standard for 35mm). Some of the challenges were minimizing diffusion, minimizing internal enlarger reflection, minimizing chromatic aberration.