The magnetic closure would need to go on before you pull it through...you would want it just on the lining. Sorry, I don't have my pattern here to look at it right now to see exactly where I will do it. Also, I always stick a piece of fusible fleece behind the spot where I am putting the closure...gives it more stability. Maybe I will need to pull the fabric through and then mark the spot and then pull it back through.
Gosh...sorry, I know this is about as clear as mud. I spent the day in my kdg classroom trying to put away all the stuff that came with our new math series...and, they don't see the need to have the air on when kids are not there (and our windows do NOT open). It was 93 outside and I think about that in my room. I am pretty much worn out tonite.