1. You surely have the unsharp masking filter (Ai
version) or the auto sharpen filter (SE
version) switched on, which is the factory default setting. This is the reason, why the images look more sharpened after the scan. There is no way to display the sharpen filter on the preview, because sharpening is very much dependend on the scan resolution and normally the prescan is done with another resolution than the final scan.
2. SilverFast can rotate and flip the images on the preview and at scan time. Beside the preview window, there are icons for rotating and horizontal / vertical flipping. Using these icons, all frames will be rotated and flipped and the preview is also displayed rotated and flipped. There are also rotate / flip icons in the densitometer window. These icons rotate and flip individual frames but not the preview. You will need the icons in the densitometer, if you want to rotate one frame, but not the others, or if you want to flip one frame horizontal and others vertical.