Spoof your location in Find My Friends. Enter coordinates in [Settings]--[FMFLocationSpoofer].
This tweak was previously released as "Find My Friends China Location Patch". Now it supports location spoofing. Location shift fix for mainland China is automatically applied. Your un-jailbroken friends can see your correct/spoofed location without shift issue.
No background process running. It patches FindMyFriends.app and aosnotifyd directly.
You need to restart BOTH findMyFrineds.app and aosnotifyd for it to take effect. Restarting your phone is probably easier if you don't know how to do it from terminal.
I have a blog post about how it works: blog post
It's completely open source. You can find the source on Github
Configure options from Settings.
==Known issue==
Does not patch the background location reporting process correctly(aosnotifyd). If your friend does not have this tweak installed, he/she will not see your shifted location when your FMF app is in the background.