Thanks for the replies, y'all. I ended up ordering a version of mGB with the offset midi channels from Catskull Electronics. This solved my problem without having to introduce any other bits of hardware, which is a plus for me.

It is a shame Cynthcart can't cycle through all midi channels, I have the same dilemma and don't really want to set up my akai force to solve it. A small midi routing box like Jekyll suggested is the way to go and will solve the same problem on any other devices you add that cant set midi channel either.

You could buy a Blokas Midihub and route and change Midi channels to your liking. Works great for me, and opens a lot of other possibilities too!

Alternatively, if I could get a version of Cynthcart that allows Midi Ch 6+, that would solve my problem.

I'm running into a bit of an issue sending midi out to several devices at once. I'm trying to get my Cynthcart, mGB, and MidiNES to all work through 1 midi device. I can't currently run Cynthcart and mGB at the same time because Cynthcart wants to use Ch1 or Ch5, and mGB uses Ch 1-5. I'd like to offset the midi channels on mGB.

I'm trying to use the Max Editor for Arduino Boy (https://github.com/trash80/Arduinoboy#max-editor), but it doesn't seem to be working correctly. Trying to reset to default for instance gives me some weird results with jumbled up default values. I'm guessing maybe this is due to the difference in Arduino vs Teensy hardware??

Is there a way for me to offset midi channels on mGB with a Teensyboy Pro? If not, I may need to order a cart with the hard-coded channel offset (preferably mGB_1_3_0-ch11-15.gb so I can use MidiNES on Ch 2-6). That rom is found here: https://github.com/defensem3ch/mGB/releases

Any thoughts? Thanks!