Speaking of which... there's several reasons Hydra's partnership with Orion will be ideal...
One... The best area to search is probably the ruins. Every time Ophiuchus has been deployed, it has been in that area. I've been told there's some connection to the past there... and I had noticed Hydra had completed a mapping mission there. We've been out extensively.
Two... The searches are best conducted after curfew. It might not be enough to cover a keystone being moved, but with a means to hide it, we have a better chance of losing opposition in true darkness.
With the lanterns that Ophiuchus has, the Old Man will not be as active in that circle... I assume you wont have any problems getting a lantern yourself if we have our own means?