Technically you can send 3,125 bytes per second on a MIDI cable (that is the speed a MIDI interface) and considering that the typical MIDI message is 3 bytes, it can more or less send one message per millisecond. It’s variable because o other messages, e.g. MIDI clock or active sensing. That ought to give you an idea of what you are facing in terms of timing.
I use several MIDI splitters (one port is split into more ports, exact copies of the original) so that each device gets their own cable. Each of the out ports from my Midex8 goes directly into a MIDI patch bay (with 16 ports in and 20 ports out) and each out port from there is connected to a 1/4 splitter box (small and very fast). So essentially all of my equipment is constantly connected, and available with simple commands or via button pushing.
The same thing goes for keyboards, drum machines and other controllers coming in. They are summed by MIDI mergers (this can be a little trickier depending on the devices) and those are routed to the Midex8. Some devices just don’t play nicely with others!
