Having recently played a craft-magus, I will pitch by two cents to this topic.
The main challenge you will face, if a mage wants to create beautiful things by magic is to have the highest Finesse score possible. Not a spell, but a skill.
Since you mentioned you are a new player, let me break down the issue.
Spells are tools that can do many things, but the quality achieved by such spells are limited by the mage ability to finely control his/her magic. And this is achieved through the Finesse skill.
You will likely find on this forum explanation of the difference between using Creo magic (which bring from nothingness complete structure/creature), versus Rego magic that mould and shape existing material to the whim of the mage. But both hit the limit of the mage's skill: Finesse.
You will find a lot more details into HoH: Societas in the Jerbiton chapter.
In a nutshell, Finesse is very versatile and can be used with any type of magic to shape stone, leather, bone, wood, etc. The downside is twofold: first, there is a price to versatility and it means that in term of Ease factor, an object crafted through magic and Finesse is always at least 3 points higher than done through mundane means.
Second, because magic happens instantaneously, the longer the mundane task to manufacture said object or structure, the more difficult it is to replicate by magic.
For example: assuming a skilled craftsmen would build a wooden, cosy hut in, let's say a season of work, with an Ease factor of 7 (functional, neat, tidy, nothing fancy). A mage with the right spell can do it within a few seconds, but the ease factor will be 7 +3 (craft magic) +6 (a season's worth of work done in an instant) for a total of 16...
So if a mage wants to go that way, Affinity, Puissant and Cautious with Finesse are three virtues he will need.
Spells' level will range between 15 to 25 for most for crafting spell, possibly 35 for Conjuring the Mystic Tower (creating a tower, not building it from existing raw material), so Art level requirement is not as high as you might expect, which allows the mage to get Herbam (carpentry work, furniture), Terram (masonry, metal bits) and to push it Animal (for tapestry and other interior design)
By canon, it is not really possible to increase the level of a spell just to lower the Finesse requirement. It is not a bug, but a feature to prevent non-magic craftsmen to become obsolete so they keep having a purpose in the game. It can be houseruled, but discuss that with your troupe beforehand.
Additional skills to consider:
- Profession: Architect
- Artes Liberales (covering knowledge of perfect ratio, geometry, etc...)
Have fun.