I have a minibrute ,great synth. I think the way I might go about doing this would be to use the arp on both the Minibrute and the OT. Try setting the Minibrute arp to “on” and set the length division to half what you set the OT to. Basically you would have the OT playing 1/8 notes and the Minibrute playing 1/16, so the Minibrute plays two notes for every one note the OT plays. You could also play around with the timing of the Minibrute live for some extra rhythmic effects.