If I ever need to copy between instances, I use the + register for the system clipboard. There is only one but generally it's good enough for me. If I'm expec

If I ever need to copy between instances, I use the + register for the system clipboard. There is only one but generally it's good enough for me. If I'm expecting a lot of copying between files, that's when I will break my own rule and temporarily use a split window inside vim.