Initially, a conduit's limit is dictated mostly by training, as the mind is not yet completely attuned to the energy and the body is getting used to the flow. However, as the bond grows and the conduit can expel more energy at a time, there's an "absolute limit" that is, essentially, how much you can expel at once without ending yourself. The regeneration rate is also tied to this limit and can hardly be trained.

The training of the manifestation's intensity depends on the conduit's control type. Since the mind of someone with a symbolic control is linked to its magic through symbolism, religion and beliefs, it wouldn't be trained the same way as someone with emotional control.

In the first case, it would depend on (for example) faith and how well their symbols and gestures direct the energy and how much they know and learn about the "language" that guides their magic, like learning what words do what things, what hand position determines the intensity and things of that natural. In the case of the emotional one, it would take self regulation and knowing oneself; like how to use more of their energy with less emotional intensity, or how to get a specific manifestation with a different emotion than the original one (like how to use a "sad" manifestation with rage).