Hi there,
well DM1 is sort of a difficult child midi wise. Forget about actually syncing this properly. I havent managed to and DM1 doesnt react to Midi Start and Stop. Also the whole Midi thing in iOS is pretty much a mess. Cubasis is from my point of view the most stable App when it comes to Midi.
What I usually do is sequence it over Audiobus but not recording it. Instead when done I bounce it in DM1 and import it into Cubasis. Otherwise you will be off a tiny bit, as there isnt the needed precision in actually making it loop properly.
Thats why quite a lot of Cubasis Users whish for a Loop Feature in the Audioplayer as for example Audioshare has. So you can control your loop while adjusting the boundaries of it.
Best regards