Q: Cutting sprouted russet potatoes in half for planting?

[nickel plate]

They've been in the dark basement for about a month+ and the eyes are generously sprouting. I have a dozen about 4+ inches long organic russet type potatoes so my question is how to go about cutting them down the middle perpendicular to the overall length as to produce two equal active pieces or just plant them whole and be done with it.
This is my third year of raising potatoes in the central valley of California but in the past it's always been smaller seed potatoes, no cutting necessary and decent yet small sized harvests.
Also planting three dozen red seed varieties that will be dropped in at the same time.