I solved for this by simply giving Windows and Linux a hard drive each. The boot records are completely separate, and neither one tries to read data from the other. (Personally I have no need, my NAS handles any file level syncing, but that's minimal anyway.) Both Windows and the Linux boot are registered in UEFI, so I asked my BIOS to disable the hard drive preference and pop up the boot menu each time, letting me pick which OS to use manually.