Interested bystander, but no MB3 here. Just working from the MIDI Baby 3 Editor, so correct me if I’m wrong.
I see a count & send option for a Program Change. Start & Stop PC; Step; Count to configure. That should get you incremental presets on a switch action, scrolling upward. I don’t see negative number entries, so I’m not so sure about scrolling down.
Send Single Value (or Send Counter?) could bring you back to a starting point preset [PC #1 of 25, for example). I don’t see where that Editor currently supports programming more than one Main Footswitch, though.
So, I did what they recommend. You can send multiple PC commands (PC0 thru PC6) in sequence on one switch to scroll up on the MB3/Rose. Then I just assigned (0-6)PC numbers I wanted to H9 presets. But, there’s no scrolling down you have to cycle thru all 7 commands. With this method you lose the hold & long hold on MB3.
If the pedal had scrolling on a specific PC or CC number, you could just use those commands to scroll up/down. Then I could go to the H9 & just use the same PC or CC numbers as the Rose to scroll up/down.