if you plan to use the hop rocket as a hop back to increase hop flavor....consider you just wasted hops. Where others on here did an experiment making an IPA using the hop rocket as a hop back, I made a 15 IBU beer that had only one addition of hops at 60 min. The hop rocket was filled with 3 ounces of citra and there was near ZERO hop aroma pick up. However, the hop rocket filtered the beer pretty well.
If you want to add hop flavor/aroma using a hop rocket then use it as a randal. And consider passing more than just 5 gallons through the hop rocket. the first gallon or so is super grassy beer but it gets better.
I think using the HR as a "torpedo" may just oxidize your beer no matter how much CO2 you try to purge through your lines. SNbco uses torpedos mainly because its pretty damn hard to dry hop an 800 barrel fermenter.
Its a fun toy no doubt. and I'd say try it for yourself and see how you like it.
I'd be interested in hearing if you've tried this again and had the same results. The reason I ask is that your experience sounds unique to that of other users. I'm picking up a hop rocket and would be interested to hear about what works/doesn't work for adding hop aroma/flavor.