Instead of manually uploading your MIDI file from your computer to cloud storage, then downloading it to your iPad, then attaching it to a recording on your iPad, you could just attach it to the recording in the BandHelper website on your computer. That's easier and also reduces the number of copies of the file you have out there -- you would just have the file you export from Logic, and the BandHelper manages internally, which it will remove when you update the recording with a new file.