Yea! You did it! I'd say your nailed it. I love the black and white one! You're right, once you get the rhythm/pattern down, it's easy.
I did one with some other kind of poly ribbon and grosgrain. It wasn't as easy. It tended to want to slip more. I also did one with some striped ribbon I had. I used the measurement with the instructions. But when I was near the end, I found I ran out of ribbon. I think the stripe may have been just under 3/8ths, so by the time I got to the end, it was too short
Just using solid grosgrain, the measurements in the instructions worked fine.
Congrats and looking forward to seeing more of your pics!