The further I go into the "trout spey" the more I'm inclined to say its not for the the Sex Dungeon enthusiast...which is damn disappointing.
There is no way around the fact that it takes mass in the line to move the mass of the fly.
You want to throw heavy flies you need a heavy line. A sex dungeon has about the same weight as a normal tarpon fly which is cast with a 10 wt line... it stands to reason you need a switch line about equivalent to a 10 wt tarpon line give or take.
That puts you in about the same range as your winter steelhead rods..