@redenkri: As far as I know you can flash whatever ROM you want, China or Global,
as far as you keep your bootloader UNLOCKED.
So never lock it again when you are flashing differents ROMs with TWRP!
You only can/should lock your bootloader again, when you decide to stay with the ROM channel which was originally intended for your device - in your case China ROM, as I understood your OP.
Someone please correct me if I'm wrong with my assumption.
Edit: Someone please correct me if I'm wrong with my assumption.