Q: Migration Advice

Hello, everyone.

I'm going to be migrating from Aperture to Photos and need a little advice to make it as painless as possible.

I currently have a referenced Aperture library of about 190 GBs with the original files stored on an external HDD. This library will not fit on the SSD of my MBA. What will be the best course of action to take to get the photos into Photos then uploaded to iCloud.

Based on what I have read I can tell Photos to open the Aperture library, and that's all I really have to do for it to import and start uploading the originals to iCloud. What I'm not sure about is will Photos try to copy that 190 GBs to internal storage, or can it leave the original files where they are, on the external HDD, and upload them to iCloud from there?

Advice will be appreciated.

TIA,

Michael