When using the iPad, I have eight (but minimum I need is five) drum units each responding to four midi commands but on separate MIDI channels for each of them.
Can I use a different MIDI channel per"page" of the Midi Maestro? I want the same actual midi commands on each page, but on a different midi channel.
Yes, this is absolutely possible. When creating a MIDI command, you can adjust the type, channel, command, and value. You can simply use a different MIDI channel when setting up the commands on each page.