Mia, relax. As far as I understand, we aren’t talking about the final delivery for your client but rather a preview, right? If that’s the case, you don’t need top notch quality but rather something that looks nice. So make a 1GB file – h264 is your best friend here – and upload it to whatever website fits you best. It can be Vimeo, or it can be any cloud service.
And, once the job is done, you’ll give it to your client in whatever media you have arranged.