I am a bit overwhelm by the number of books now available, so I am looking at this group to have some advices.
I would like to build a mage around the concept of magical crafting, specially gifted in building things for his sodales, and possibly even for some friendly non-magus. He would be contacted by spring covenant, lonely mage or mage looking for discreet job to build room/lab/house/inn without resorting to Creo magic and vis expensive ritual (I know that vis abundance is relative for each campaign, so in this case, assume that only well established covenants will be willing to spend virtus for tower building).
The core virtues I identified so far:
Affinity Finesse (is having both overkill ?)
Major focus: manipulation of physical object (non-living), basically, encompassing ReTe, ReHe (wood) and possibly the odd "bone-made" throne.
... which leave plenty of room.
If having score in relevant mundane knowledge helps in the building process (Craft: Architecture or Masonry), I could easily see Apt Student, as he will broaden and diversify his building skills.
I am always partial to Inventive genius, to make the research of specific spell easier, and I am also considering Free Expression to let him build truly creative structures.
As flaw, I would easily see:
Weak Spontaneous Magic - I see my magus as a methodical, slow builder, not so keen on improvising stuff which might collapse. However, he might be having "Flexible Formulaic Magic" as a virtue: he can be creative once he has learned something.
Waster of vis - which could explain also his choice of magic.
Emphasize will be on Intelligence and probably Perception - the two main attributes which could be relevant for Finesse and construction.
House: It is not clear cut for where such magus could come from. A forgotten tradition in Ex Miscellanea coming from menhirs crafter ? A Mercere helping his house establishing network of inns and trade house ? I guess, it will depend on the Virtue/Flaw you might suggest.
Arts: definitely Rego, Muto, Herbam and Terram as his priority. His magical focus should help him handle the various requisit.
For spells, I was wondering if it would be possible to invent spell allowing to only partially build items, requiring several spells to achieve the final results. The idea is to be able to achieve higher Artistic value by decreasing the Finesse roll target. He might have to spend a whole week to build a house instead of just one spell. Maybe he need to invent spell with Duration "Concentration" ("The five Masons at work"), and need high concentration score and good stamina.
Artes Liberales (geometry) - I guess
but what else could help ? Some social skills to negotiate ? some drawing skills or craft skills to put his idea on paper and show it to his customers ?
I am looking forward to your suggestions.
I do not want a one-tricky poney, I would rather look at a well rounded character.
Following all suggestions, I am updating my magus here
Hieronimus Fafnerson, House Ex Miscellanea
Strong Faerie Blood (God Blood, Fafner) - Free Ex Misc
Puissant Finesse - Free Ex Misc
Weak spontaneous Magic - Ex Misc
His Master Westi the Woodbender, a Rustician magus. When he took Hieronimus as apprentice, Westi was not able to initiate Hieronimus in the Art of the Rustician magi, however, he clearly felt that he had all the potential to be a great Craft-magus, so he trained him the best he could.
Virtues: 5 minor
Faerie Legacy (necessary to enjoy the Sympathy benefit coming from his blood)
Affinity - Finesse
Waster of Vis (major)
Warped magic (minor)
Faerie Upbringing (minor)
Int: +3 (+1 from Improved characteristic)
Early childhood - no social skills because of Faerie Upbringing
Native Language: Danish: 5
Second Sight: 2
Faerie Lore: 2
He was found at the age of 8 by Westi after being adopted by a small farming community after leaving (or being abandonned ?) the court he was living in, he had learned by that time:
Language: German: 3
Area Lore: 1 (5)
Magic Theory: 3
Artes Liberales (geometry): 1
The choice of the Arts was dictated to be able to cast The Mystical Carpenter (ReHe25), The Phantom Blacksmith (ReTe20) and a few other spells that I will design later on.
The Mystical Carpenter (ReHe25)
The Phantom Blacksmith (ReTe20)