All material for the outdoor performers should be selected at will and on an individual basis: changes of material do not need to be co-ordinated with the other players; everybody playing the same material or everybody playing different material are equally fine (and everything in between).
The performance should be undertaken with a deep, considered kind of listening, but this should be a listening that focuses on the bells and their impact on the sonic environment as much as (but not more than) on the other musicians playing outdoors.
Density and intensity of material will not be controlled at all by the composer and can be freely decided/improvised by the outdoor musicians. Not playing is always an option, but it’s possibly worth bearing in mind that the audience will come and go and individual audience members may get confused if all they witness during their visit is silent musicians!
Find interesting overtones in the sounds of the bells, and latch on to them. As time passes, try to continue finding new tones (through listening deeper, through the acoustic properties of new areas, through aural hallucination).
Play these tones either as long drones, or as shaped ones which taper and sit above and below the sonic environment at different moments. If you find your drones are interacting with those of the other outdoor musicians, feel encouraged to sit in that mutual space.
Especially if you are in a part of the grounds where a particular resonance is notably powerful or striking, find those frequencies and find tones that beat against it: find multiple beating tones and play them all; cycle between them; vary intensity and duration; introduce silences; if you find something especially juicy, please enjoy it!
Catch a series of frequencies, impulses, occurrences in the sonic environment (not necessarily just the bells), and turn it into a fragmentary motif. Once you have your fragment, stop listening to everything else. Play it again and again, varying the gaps between it, developing it gradually into something new. Allow it to unfurl into a melody or collapse into a series of noises.
Intensity and density can be freely chosen, but aim to have a single trajectory any time you play a fragment, and once the trajectory is fulfilled, fall silent, move to another material type, or create a new fragment.
Drone interplay based on overtones you heard in the bells while they were playing; as their memory fades, draw progressively more inspiration from other sounds around you.