I'm not sure kombucha is the best thing for diabetes. I was making it, but then I stopped when I came into the pre-diabetes range. I haven't been back in it since I stopped kombucha. Some experts like Sandor Katz have expressed some concerns about kombucha with diabetes. Kombucha is super easy to make. The more appropriate question is to ask-is it a good idea for you?
I read a lot about "black seed" as helping diabetics reverse their blood sugar issues. have you done any research on that? I was also starting to become prediabetic before overhauling my diet to a Weston A price type diet. That was 2 yrs ago and no problems in that department thus far. I would probably wait on the kombucha, you may have to ferment it so long that it wouldn't even taste good.
Those are the largest trousers in the world! Especially when next to this ad:
watch all of the video of a full, in person, permaculture design course