This is interesting. Thanks for posting.

CHB, you said the pdf shows the truss "except for the omission of the angled braces in the rectangle"

Are you talking about angled braces from queen post to top chord? This is the only way that I could see to help with deflection of the bottom chord. Without something holding up the top chord in the "rectangle" it seems that the top and bottom chord would deflect equally given they have the same span (minus the load of the lath and plaster on the bottom chord). But if the builder was trying to diminish the deflection of the bottom chord so the ceiling would not sag, it seems you would have to prop the top chord (as close to the mysterious kingpost as possible) back to the queen posts. I guess this could keep the top chord from deflecting, and with strong joinery between "kingpost" and bottom chord keep the deflection to an acceptable minimum.

No engineer here, just a layman. Anybody else see plausibility in that? That is is, I am describing the omitted braces correctly.

P.S. The forum is acting a little quirky for me too, with posts across areas