Speculation: I can imagine that the op ran into the same issues placing the Castle modules in a Vessel that I did. The only spot I could fit the collection in mine is shown in the top two rows of this rack:
This stems from a combination of:
-the depth of the Castle modules
-the angles of the side of the Vessel (can’t place modules flush to side wall)
-the placement of power input circuitry, RCA bulkhead, and cooling fan prevents placing modules near there
-the power bus boards and depth of modules don’t allow for placement directly above them
The space I placed my Castles has nothing pinching theirs placement in the space. Still, the depth of the PCBs on a few of the modules make them nearly flush to the bottom of the case. This all adds up to 8 deep and narrow modules needing to get plugged into power. In a part of the case that is offset from the power bus boards which are to the side, not directly below the modules. A single custom cable connecting all of them together makes fitting them in a lot more manageable.