iMovie to YouTube
I use SHARE/MOVIE in 1920×1080 size save to to my desktop.
Then I go to the YouTube website and upload there.
This has several advantages.
1) I can upload videos longer than 15 minutes (YouTube will invite you to use this feature
after you have successfully done a few videos)
2) I can upload multiple videos in a batch while continuing to work on other movies.
3) If something goes wrong, I can tell if it was in the export or in the upload.
iMovie to iPad
I use software Tipard ipad transfer
just connect ipad to usb on mac or pc and file add file, the video sits on your ipad ready to play