Epson flatbed scanners are capable of no more than 1200 samples per inch across the length of their moving sensors when using "Area Guide," i.e. the device's lower resolution lens. Achieving even that much is predicated upon 8x10 film emulsion being at the point of best focus. Although there's sample variation, the manufacturer's intent is that the lower resolution lens' plane of focus is above scanning bed glass by the thickness of sheet film base. Doing opposite of what the instructions say and placing 8x10 film emulsion, rather than base, down on the glass might be great for avoiding Newton's rings, but there's a good chance focus will be noticeably off.
We're back to a likelihood-consequences situation. Given how imprecisely the plane of focus is positioned in Epson V-series scanners, there's no way to know without trials on your particular V850. If it were my choice, I'd go with 320TXP. Or at least buy one 10-sheet box of 320TXP, clear a sheet in fixer without first developing, then use the washed and dried blank negative as a spacer upon which you can place any other 8x10 film emulsion side down, subsequently flipping it in your software program of choice. That will put your negative's emulsion exactly where Epson tries to put its low resolution lens' plane of focus and still eliminate Newton's rings.
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