Hibiscus users, how much should I use?

My experience with brewing consists of a small batch of mead by the end of last year. In that batch I thought I'd be super cool and original by adding a handful of hibiscus to the contraption I made and it turned out amazing. I then found out this is common and I'm as original as the color white.

Anyway I just got gifted by a great friend a standard fermenting/bottling bucket(he was going to send me the full kit with two buckets, but then the box was 1" over the limit for shipping. Such is my life), and have been holding onto some amazing wild honey from deep within the jungles of my glorious land Brazilhue for months now, which I now intend on using to make the best mead ever. Since the hibiscus deal turned out alright, I want to add it again, but from last time I just remember grabbing a handful and tossing it in the pan. I have no idea how much should I need for a 5-gallon batch.

Also, I'm out of cinammon sticks, I guess the powdered stuff is okay? Thanks in advance guys