Producing to devices "Apple", worked for me to download and view 4 videos. When I added "slideshow"s the video, iPad would hang hung every time.
Produced to MP4 different quality formats would sometimes worked, sometimes wouldn't download (What is up with that Apple), and sometimes would hang video but continued playing audio.
Started from non-edited production to gradually add title, end, photos, and music to "Apple" preset without issues, producing, downloading, or viewing.
When I used the Magic "Slideshow" builder: various types of transitions, no music, with PD9 music presets, and my music, iPad hang up the video but audio continued.
Have now decided to use "Apple" for Devices and make my own slideshows with PD9 tranisitions. I will use my music. I have now used this format several times successfully.
Hope someone can learn from what I have written here.
Feel that I can edit and produce a good video for viewing on iPad now. Amature does it till he gets it right. A Pro does it till he can't get it wrong.