2X and 4X seem to pull more detail on mine. Scan times increase significantly.
If you have a long scale subject, make two scans, one for correct highlights, one for shadows. Treat like HDR.
OPen both in PS whith light on top. Temporarily change blend mode to difference. Activate move tool, V shortcut, and use arrows to align layers. Usually mine are right on.
USe HDR to combine or even better, a luminescent mask on the top one, highlight layer.
Go to The Lights Right.com, digital darkrom tab, video tutorials, blending images for more details.
Put your negs in a plastic sleeve and weight with a book to get them flat. The scanner will get every grain corner to corner sharp.
Tri x scans best. Keep development to low contrast for best results.