Am I the only one who thinks Cruiser Solaris are somewhat decent?
All you need to make them good is the ability to chainfire, to have a couple of BRs ready and decent aim. Though, their DPS is somewhat low, so you need 8 to be properly effective.
Though, the only Cruiser I've got Solaris on is my Praefect, and it is pretty much one of the best Cruisers around (insanely good firing arcs, small profile and it is somewhat agile for a Heavy Cruiser), so I'm not sure how they would work on a Scylla, which lacks many of the Praefect's attributes.
Still, there are lots of loadouts out there that work, and often some of the more unorthodox ones can turn out to be really good, so go experiment.