If you subscribe and find that Adobe Send doesn't meet your needs, you can cancel within 30 days for a full refund.
Sending files as large as 12GB might be a problem; the service is designed for files up to about 2GB.
Upload speed will depend on your own internet connection. And consider your recipients' download speeds, as well. I would suggest that you subscribe and give it a try.
For file-type restrictions, see: https://forums.adobe.com/docs/DOC-4472#filetypes