I found a drop dead simple way of doing this, at least for a person like me. Control iOS was configured to send to my computer on port 60000. So what do I do? I listen to Network Traffic.
From the terminal, run
tcpdump -v -i en1 'port 60000'. (Note that en1 is my wireless interface, you may have to consult the output of
ifconfig to figure out your interface name.) Among the multitude of other lines while drawing my finger across the application's space, I saw:
17:46:43.789027 IP (tos 0x0, ttl 64, id 42497, offset 0, flags [none], proto UDP (17), length 72)
192.168.1.109.53578 > 192.168.1.110.60000: UDP, length 44
Considering I had a rough idea what an OSC key name looked like, I plugged
/multi/1 into the OSC Receiver block of Quartz Composer, and I had control over the circle used in the example!
Note also that XY type communication occurs as "floats". NOT FLOAT, but plural, "floats". Because it's a float of the x-axis, and of the y-axis.
If your input does not take a structure, you can use the
Structure Index Member or
Structure Key Member Patches to isolate the X or Y value, and put it into your input patch.
Note that I'm still very interested in a simpler solution to this, especially for readabilities sake. If I wish to test multiple buttons quickly, the tcpdump text will be scrolling too quickly for me to be able to adequately read in some cases. So, I will not accept this answer if it goes over a week without any other answer.