Ipad Garageband <-> Mac Book Pro - Logic X or GB exchange

Hello

My question concerns working between these two devices apple devices and their software

My student will work during the week recording ideas and parts on his Ipad

To not waste time with the Ipad interface, during the one hour weekly lesson, I will transfer the project via itunes to my MBP, and record new things.
So far I have that covered ,

But then I need to give him back the work we've done , so that he can continue it on Ipad during the week.

Meaning transfering the audio-files back to GB Ipad

Q: Under what format and How (step by step)

If you have an idea for an easier way to do this it will equally great

I Hope you can help

Kind Regards

Vaughn Hollund