Buy the lowest tier, you can upgrade any time. Whatever you have in it is applied to the next tier. You don't know if that client is going to continue using that scanner. Plenty of offices use them for door stops.
Unless things have changed, the doctor gets software for the office to track scanned cases. This software can also download the stl files once the scans have been cleaned up and the margins marked at Align.
If you have a good relationship with this client and they are local, go to the office and call Align tech support. They will show you how the software works and how to download the stl files in your preferred CAD design format. Take a flash drive and pick up all the cases without carrying case pans. Once you are familiar with the process teach one of the office staff how to do it and upload them to Drop Box or similar FTP service.
Pretty sure you are exo user. Model Creator module msrp is $1200 last I looked. It was designed specifically to design models from IO scans. Your reseller will drop a license key for it on your work station. Restart the software and presto your ready to design models. Or you can just try the iTero models for a bit.
I agree with the Aussie, you will have more and more clients going this way. If you are a small operation you don't have to get everything at once. If you really are unfamiliar with the work flows you will be better served to ease into it. You will make wiser decisions after you gain some experience.
to User Name. He's not as nutty as he'd like you to believe.