As far as I know, there are two sets of guidelines for Rego Craft magic -- those in Covenants, and those in the Jerbiton chapter of HoH:S. These do not appear entirely consistent; furthermore, they are not entirely clear.
First of all, it's not entirely clear when your Target should be Group and when it should be Individual. Arguably, if you are starting from multiple stones, multiple wooden logs, or multiple iron bar it should be Group. However, is a mass of flax or wool an Individual or a Group (a multitude of little strands)? Also, HoH:S p.61 provides Rego guidelines whose "levels are correct for all spells that make items of Individual size, at Touch Range, with Momentary Duration." -- which seems to suggest that if you are making a single item from a bunch of components, the Target should be Individual rather than Group.
This latter sentence also seems to imply that the guidelines given in HoH:S already incorporate the +1 modifier for Touch. However, if we compare them to the guidelines in Covenants, there are inconsistencies. For example, building something from timber uses Base 1 in HoH:S if the timber has already been "prepared", Base 5 otherwise. It's Base 3 to Base 5 in Covenants.
Finally, the guidelines in Covenants are not entirely clear about the difference between "manipulate an item", "treat an item" and "treat and process an item". I guess that "manipulate" includes plain assembling -- so you can build a hut from some timber if you could do so with your hands and a hammer. But what if a saw was needed (e.g. to cut planks to size)? Would it still count as "manipulate" or as "treat" or "treat and process"? I also guess that "treat" means stuff like seasoning wood, baking clay, and dyeing wool. Would washing and cleaning fall into this category or into the easier "manipulating" one?
And I am not entirely sure what "treat and process" means -- is it just a combination of "manipulate" and "treat" or is it something different? If I were to hazard a guess, I'd say that turning raw wool into wool thread is "treat" (but MoH, p.57, seems to imply it's just "manipulate"); turning wool thread into a garment is "manipulate"; turning raw wool into a garment is "treat and process" (MoH, p.57 seems to confirm this, but then uses Base 2 rather than the Base 3 guideline in Covenants).
Is anyone willing to help me sort this out? Ideally, if we could come up with something systematic, nice, clear and consistent in a unified document (probably one page at most), we could ask Atlas to host it on their website!