Where to put the zipper?

Hi all!  I want to make this dress using Simplicity 2892 for the top and probably S2724 for the skirt:


So.... I want the top to be a little blousey (poofing up over the skirt, not fitted like the top in 2724) and I can't add a back zipper because 2892 doesn't have one.  I'm scared of adding one and messing up the cute yoke.  I need to add a zipper to the side, but will that affect the blousey-ness of the top?  Do you think an invisible zipper will move better with the top?  I'm going to use a silk charmeuse.

Thanks!!