Yo I love black hops! It was one of the tricks we did for trick a week and you can see some of my tips and a discussion about the trick here.
The most important rec I can give is to take your time! There is no need to rush and it is better to pause at each hop and make sure you’re set up for each consecutive hop. You want to point your fingers down to scoot the string to the back of your fingers for the first hops and then try to undercut as close as possible to the Yoyo, with the string right at the tip of your fingers for the last two hops. This helps maximize the space available to land the Yoyo. Once you get comfortable with each of the hops in isolation, then try to smooth it out and speed it up. Good luck!!!