I say to you further that, if the quantity of stone of which an image is composed is large (that is, between an ounce and a pound), the virtue and power of it will be able to reach from the place where it is for a hundred leagues.
If it contains a combination of things in its figure, however, its nature will have no motion or effect except that which terminates in its own place, though its motion or effect will not be limited to those of its substance or the nature of the bodies that compose it, for spirits have a wider range than those bodies that contain little spirit.
–Picatrix IV:4, Greer-Warnock translation
Talismans made from mineral spheres of even medium sizes will project power for 300 miles in all directions.
Talismans which attempt to draw upon the power of more than one celestial hierarchy will be crippled, like a chariot whose horses are running in different directions.
They will have some influence in their immediate environment because they are inhabited by a chimerical spirit, but less than a pure spirit and more than the natural virtues of whatever material the talisman is composed of.
On that note, I hereby coin the term chimerical spirit; a temporary union of astral spirits from dissimilar celestial hierarchies in a talisman, which being neither fish nor fowl operates with the virtues of neither.
This notion seemingly creates an inherent limitation upon House-based talismans. Which may explain why I have found them ineffective and frustrating.