If you don't mind having something like a Samsung T3 external SSD or a high-capacity high-speed USB-C flash drive plugged in when using media, I think you will be able to get by (although it may be slightly less convenient.)
I'm not sure if this interests you or not, but, depending how you use Windows 10, you could use a program like VMWare Fusion to run a Win10 virtual machine, and enable shared folders between the host OS and guest OS so that you do not have the redundancy of the same DropBox files on the computer 2x. If you ever wanted additional Windows, Linux, or OS X guests, it's easy to run them off of an external SSD or flash drive. The simultaneous access to both a host and guest can be nice - the primary exception being extremely intense applications and gaming.