Yes, you are correct. That is 8mm res tech, and a single bite of rope that small can be pretty fast.
I have never been trained to use 2 strands of rope with a ring, my initial thought is that it would cause you to have to move up to a larger rappel ring, and before I acquired that expense and carried a larger ring I would recommend either using a figure 8, or one of the many tube devices on the market today.
But I’ll try it someday, I’ll video it and throw it on my channel and post how it works.
That looks like 8mm rope. Can you put two strands with a bite though that ring? I'm planning on using the JRB method and while I know the munter hitch works...I'm just curious as this might be a better way.