Spelltracing involves tracing a pattern in midair, called a sigil, with a certain gem called magicite. Spelltracers believe that the soul trapped within the magicite, even though it cannot interact with the world directly, can still sense itself being moved.
Complexity considerations: Particular patterns beget particular spells, with the more complicated spells being the ones that have the more specific patterns that take longer to trace. If a trace is traced incorrectly, nothing may happen, or something unexpected may happen. More complicated traces are more prone to failure as they involve more steps. Tracing larger traces with smaller magicite increases chances of failure as it’s more likely that the smaller stone will fall ‘outside the path’ at some point in the tracing process.
Standardization considerations: Spelltracers go to the College to learn the patterns for each spell. Each pattern only has its particular effect because spelltracers believe it does, which explains why these patterns which seem to have nothing to do with effects, would have any effect, and why many the same spell may have multiple patterns, etc. Many spelltracers do research to try to identify patterns, but they are only tricking themselves into believing in patterns, thereby making those patterns effective, thereby inventing new traces. By having all tracers go to the same college and attend the same lessons, the College standardizes the effects of these particular patterns.
Scale considerations: Larger versions of the same spells require larger traces (sigils), which in turn requires larger magicite and larger staves to move the magicite, and teams of people to move the staves, and this acts as the limit on the power of spells. At the smaller end spelltracers have miniwands with 1-carat magicite; and then there are staves for infantry-scale combat. The magic of spelltracing is limited by scale only because spelltracers believe it does; but it comes with the benefit that they can be more confident in casting smaller magnitude spells.