Scan paper photos to find their duplicates from scanned negs

[algusev2017]

The aim is to scan black and white paper photos of 1960-1995 and find their duplicates on PC or to confirm their absence. These duplicates were made by scanning films with film scanner Primefilm3650u. I have hundreds of paper photos and I have much more files. These collections do not correspond each other. Many printed items are not from these negs and a majority of negs was not printed. The films of printed photos are not known. There are no filming dates. I plan to use flatbed scanner HP g3010 because of no alternative. And I shall use Vuescan software. I shall search duplicates by Webminds, Image comparer or other software, having scanned. The question is such. What options should be used for scanning to find duplicates with great accuracy? I put 1200 or 1200 dpi resolution, when scanning films. The rest of options were defined automatically by Vuescan. The screenshots of photos and corresponding film cadres are enclosed here. There is darkness on the screenshots of the scanned photos below and left. I made it to differ from the cadres.

 

[koraks]

What options should be used for scanning to find duplicates with great accuracy?

For prints, scan at 300-600dpi (more doesn't make sense) and make sure to not clip either highlights or shadows. That's about it.