I believe your concern is more technical which is probably beyond the scope of this Community. The volunteers here are mostly small business owners who have hands-on experience with Square's Apps and Hardware. You could try asking in Developer Forum. Note, I did find some info here - Add a Domain - section 5 - part C looks like the easiest but, Weebly doesn't allow FTP access directly - maybe contacting Tech Support to see if there's something they can do would be something to look into.
