@CreepyPants, you had an all-USB setup (to the Pyramid at least) if I’ve understood correctly?
Just tested this, and USB is quite different from DIN on the Pyramid when it comes to sync and start/stop. Buggy I would say:
For data coming from the USB port, CLOCK SYNC and START/STOP settings have no effect. USB CLOCK SYNC must be enabled for it to receive START/STOP from there. When that’s enabled, sending START causes Pyramid to start (apparently) immediately without waiting for the first CLOCK. Also CLOCK TIMEOUT setting has no effect.
For data coming from MIDI IN, things are far more complicated. If START/STOP is disabled then those are not received regardless of CLOCK settings (as expected). If START/STOP is enabled then those are received regardless of CLOCK settings. If CLOCK SYNC is enabled, then it visibly waits (literally hangs) for the first CLOCK message, but starts playing nevertheless if that clock never arrives. The time spent waiting depends on CLOCK TIMEOUT value.
So just enable USB CLOCK SYNC and those “transport” messages should start working.
Edit: Oh and yes, according to the MIDI spec, START is only a “get ready” signal, and playback should only start at the first CLOCK message. I wont try to guess as to how common it is, but some hardware and software will start the playing without ever receiving the CLOCK, and Pyramid is one of them.