Nikki, I can't wait to see your results! I haven't tried cassia on my entire head yet, just henna.
The gloss I refer to is actually a method of applying henna and cassia. If you only have a little bit (like I had a few tablespoons left over), you can freeze it. Then later mix it with conditioner (no -oil for henna) or pectin, honey, or flax gel, and use it to refresh your color or shine.