I already messaged David. Just posting this so anyone else can add in anything else.
In Magi of Hermes, p.101 the spell "Arachne's Tuition" has at least two issues.
It uses the Base 4 "Control the large-scale physical movements of a target" and functions like the Base 10 "Control a target's motions". Only having control of large-scale movements would not allow "particularly complex task". [EDIT: The spell is designed by a weaver and its flavor text talks about teaching weaving. That is fine movement of the fingers.]
It uses Range: Eye which would totally interfere with its intended function. For the Caster to have control they would have to be looking the Target in the eye (as per ArM5, p.111). It is kinda hard to direct someone through a complex task or show them how to do something while the two of you are staring each other in the eye rather than looking at what you are doing.
The Range becomes even more of a pain for changing commands after eye contact is broken since you are going to have to grab the Target by the head and force them to look you in the eye.
Fixes: Base 10 and Range: Touch.