I would say that in most consumer applications, running unbalanced 30' RCA for subwoofer connection is perfectly fine, granted that it is properly shielded. Since the source is unbalanced, converting it to an XLR connection would make no difference, so just run a 30' RCA/subwoofer cable.
You could try, though the CHT will basically be your bottleneck in the system, so it will reach its limits before the VTF-15H MK2. It's a bit difficult to gain match two different performing subs. I really don't think the CHT
would contribute much to the setup. There is a good possibility that it could detract from the sound quality due to things such as improper placement causing non-linearity, etc.