I've got an alternative pitch for this whole thing, instead of writing a full script every week, and then trying to figure out a logline for each one, why not cleverly circumvent a huge amount of that work by simply posting one test logline at a time, gauging response under pretense of designing the logline for a finished script, and then only write the scripts corresponding to the loglines that seemed to get a positive reaction.
That way you don't have to actually write several hundred pages a month, like you've been doing, you only need to write and discuss loglines.
For this logline, I think I would have gone with something a bit more terse and clear-
An assassin that was planning to kill the queen of England decided to kill some cult members instead.
Personally I feel like your logline was missing the core factors that attract steampunk fans. There is no mention of of excessively tall black top hats with long feathers and superfluous monocles tucked into the band. At what point does the hero discover a futuristic steam powered laboratory with a gold plated telescope that is used to spy on a hot air balloon covered with clock gears? Does the assassin have a monocle, cane, double breasted coat with numerous rows of brass buttons like the Beatles wore on the cover of Sgt. Pepper? There is also no mention of an extremely significant old book on an expensive stained wood pedestal inside a maximalist library owned by an eccentric but energetic professor. I just think your tagline needs to promise more of the standard steampunk fare to capture this highly selective demographic.