Yeah, harlequins are very restricted army in terms of organization, due to, of course, the lack of HQ choice...
In my case, Harles become the primary force with the allied Purge Coterie (or less frequently, CAD or AD). When I play a DE primary force, I just use The Heroes' Path, meaning no specter.
EDIT: The Blades of Fate are awesome, but I cannot find any good reason to use both troupe compositions, i.e., The Company of the Threefold Stranger & Death's Companions.
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Eldar Alliance: Kabal of the Wraithkind / Craftworld Iyanden / Masque of the Veiled Path / Ynnari Aetheriders (Log)
Slaanesh Force: Chaos Daemons / Emperor's Children (both 30k & 40k) / Heretek Metalica