When I wrote the first post I was really only thinking of leveraging the warping-free nature of the familiar bond to recreate the Crown of Hermes from covenants page 121. But now I've got six or more other spells effects that I want to hammer out. The first is how one creates a mental construct lab.
Mysteries revised has Memory palace of he sage as a level 25 CrMe ritual that adds an exceedingly detailed locus to your memory palace.
Meanwhile, the Crown of Hermes creates a mental lab with Cr(In, Mu, Re)Me 50 (Base
35, +1 Touch, +2 Sun).
I can perhaps imagine that the difficulty of creating an entire laboratory would exceed that of creating a book in a locus by two magnitudes. In the enchanted item effect there are intellego, Muto and Rego requisites. I think that the idea is that the crown is reading the target's mind and then making adjustments to the mental laboratory in response. That sort of thing doesn't really work with the model of a ritually created mental laboratory.
This is a fine place to get off the ritually created mental construct train and say, despite the wording of the mental construct lab flaw, creating one with a ritual doesn't make sense. It can't be done with a momentary creo ritual.
If you'd rather say mental construct labs are really cool, let's not crush the fun with outlandish amounts of difficulty. If you take this view, you might rationalize the extra requisites on the crown of Hermes as necessary for a laboratory that is independent of a mind, one that exists all on its own, available to anyone who puts on the crown. I'd suggest this ritual.
Installation of the Exceedingly Private Laboratory
CrMe 35 (ritual)
R: Personal, D: Mom. T: Ind.
By casting this ritual the caster creates, in their mind, a laboratory with the mental construct flaw (Covenants p 120) as follows:
"The Size of the lab (or its imaginary part) cannot be higher than the Intelligence
score of the magus. The imaginary parts of the lab may be improved as usual (that
is, Virtues and Flaws may be gained, the Refinement may be increased, and so on)
with the usual time cost, but disregard any changes to Upkeep, Health, or Aesthetics.> Without sophisticated magic, the magus cannot use the lab to bond with a familiar,> enchant items or Longevity Rituals, or teach. He probably also cannot extract> vis in it. However he can invent spells, work with Laboratory Texts, and study> Arts “normally.” –5 Upkeep, +2 Warping, –2 Aesthetics; +3 Me." This Laboratory can connect to a character's memory palace if they have one allowing their mind to roam freely between one and the other. It is not a part of a memory palace and does not take up a room of the character's available space within it.
How does that look? Feedback and criticism are encouraged.