SnippyCanto Just make a full backup on the imac and airdrop it to your ipad then go on your ipad ST3 and restore from this full backup, you will end up with all songs and lyrics as they were on the imac.Full Backup is in settings towards the bottom.
There is one problem with this easy method all your songs on your ipad will be lost, so this is why you should only use one device as a master device this is normally the one where you do all your creating of new songs, this way you always make a full backup of this device and send it to other devices, this way all devices remain up to date and with same songs, once you start doing stuff on other devices you create a big problem where everything is out of sync and its very hard to keep things in control.
If you have this issue the best way to fix this is save all your Lyrics into notepad , this will contain all your timecoded data or perhaps midi information and chords , you can then copy all the songs from the ST3 song folder you need to save to the other devices ST3 song folder then refresh this folder then copy all your lyrics data over to the other device, now copy and paste every songs lyrics into each song again, this is a pain in the ass but its the only way you can bring your songs all together on one device, once you have done this you will be fine from there onwards as long as you use one device as the master, from there its using the backup all that saves you time.