Link is no longer valid. Do you have this anywhere else by chance? Thanks much!Updated regkey to v5. Should work with more SB models now:
Surface Book and Surface Pro 4 - high-dpi multi-monitor optimization regkey for alternate 3:2 aspect ratio resolutions - danchar - Site Home - MSDN Blogs
If v4 did not work for you on SB, please try this new key and let me know the result.