I'm creating a world where magic exists but can be used by its inhabitants only in a very weak and inefficient form. Those who want to use it cannot just snap a finger and cast any spell they want. They must spend decades studying rituals and symbols and chants and learn to reproduce very long combinations of them with insane precision if they want to be able to conjure some magical effect. Unfortunately, any effect they might be able to conjure is really underwhelming. The best that a fire spell can create is a spark. Conjuring wind can only move a leaf for a couple of seconds. Invoking lightning can only give them some static electricity on the palm of their hand. Basically nothing particularly useful. Just something that rich people with thirst for knowledge and a lot of free time can study for personal interest through the books written by the sorcerers before them.
In this world technology is not in a good position too, because the world is locked in a sort of medieval stasis and complex machinery just doesn't work. By combining the situation of magic and technology, I wanted to delineate the figure of some sorcerer/inventor who considering the limitations of both approaches is able to create some sort of efficient magic and working technology by making them compensate their respective flaw.
For example, a complex crossbow cannot be built for technical limitations and a spell that makes an object chase its target is only able of changing the trajectory slightly and depends a lot on the strength of the throw. But engraving the spell on the object and using a simple spring mechanism to throw it faster than a human allows for an efficient ranged weapon.
That's the basic idea, but I'm having problems generalizing it aside from a few examples. I can think of explosives using the spark spell and some gunpowder, but nothing more that's really significant. At the same time I'd like to avoid creating imaginary chemical materials or physical laws, because it kinda destroys the whole approach by allowing overpowered effects in a non-realistic way.
So basically the question is: do you think it's possible to generalize this idea or do you see some fundamental flaw that makes it incoherent?