Not sure what else is going on in your build. The downside of the “official” 3D printed brackets and remixes is they go over the IO shield area, blocking airflow and potentially being physically in conflict with an active CPU cooler taking up some of the same space. I assume you saw this thread; 15mm SSD Mounting Bracket?.
Not sure how big your “array” of SSDs is, but one option for the HL15 would be to mount them in the PCIE slot space;
If you went with the Beast, you could look at non-45HL-specific SSD brackets like this;
or the docks with backplanes from IcyDock and StarTech, some of which accommodate 15mm SSDs.