Minimal current needed for the 28v. This is really only required as a safety interlock for initialisation. It needs to see that 28v is present so that if 115 is lost in flight it can survive on the backup. In reality as soon as the ini turns on the 28 can be removed. You’ll get a warning but the inu will still operate as normal.
when the big day arrives, remember to take a video of the gimbal starting up, so we can see any issues and advise. :-)