Thinking about technique, handling, and musical expression becomes very simple considering that timing and dynamics are the only factors under the carillonneur's reasonable control. Much of these are a matter of personal preference, so long as they serve the goal of controlling when and how loud as accurately as possible, to best express the music. Efficiency, ease of playing (relaxation and avoiding fatigue), speed, and preventing injury are also important factors to consider. I use the term timing generally since it can refer to tempo, rubato, accelerate-and-release, etc. on the level of the whole piece, a section or phrase, or small note groupings.
Though it sounds limiting, timing and dynamics allow an immense language for musical expression, even in differentiating the styles of countless players. I will be expanding this section with examples from the carillon and other instruments. The ideas below are only a start.
For the music that reaches the ground, it really doesn't matter how the keys are played. Keep in mind, though, that carillonneurs use two distinct methods of striking the keys:
In practice, players use both of these techniques where appropriate in any given piece, and many touches fall in between the two extremes. It is not helpful to refer to them as legato and staccato touches, since these terms refer to audible articulations, which pressed and struck touches cannot make. In general, the pressed touch should be used whenever there is time, though the type of touch and handling choices are closely related (see below).
Handling choices on the carillon ultimately concern the amount of alternating and hooking (playing two or more notes in a row with the same hand). Again, to the listener on the ground, handling makes no difference, unless poor choices disrupt the player's dynamic and timing intentions.
Various sources claim that hooking causes an "accent"—i.e. louder note—on either the first or second note of a hook. Where the accent actually falls usually depends on context, and more importantly, a conscientious carillonneur decides which note is louder, if any.
I have been taught various handling philosophies, including to alternate whenever possible and to avoid alternating whenever possible. Ultimately, the desired musical affect and the handling that most easily creates that affect should determine handling. Hooking at fast speeds is easier when notes are loud; at soft dynamics, the player risks the notes not sounding at all. Fast hooking requires the struck touch, which leaves less room for error since the key-hand contact time is so small.
Alternation, except at the slowest tempos, usually requires the less-reliable struck touch. Hooking can use either pressed or struck touches, depending on tempo. The video below reveals a few very important traits of handling (sorry for the terrible audio, the last clip is a slow-motion repeat of the previous):
At slow tempos:
At fast tempos:
Therefore...