Welcome to BL ,I just did my sub induction about 10 days ago. I believe my metabolism to be faster as well.
I kept using regularly the day before my induction, which was around 9am, my DOC was Oxys and I was in around 5 to 7 of them a day, I tried to slow my usage the few days before induction but didn't let myself feel any pain the days before.
I WAS ABLE TO STOP USING AT 7 pm The night before my induction on suboxone, but different people may have different results based on their DOC half life and other factors.
Use the COWS work sheet if you are Leary on taking it to soon, but IMO once ur eyes are watering and sneezy/nose runny bone chilled than you SHOULD be safe to start taking sub....keep us informed ! And good luck on your journey to a better life .