Non-root user SFTP & /var/www/html permissions

Hi,

So I set up a new Ubuntu 14.04 server with WordPress and I’ve created a non-root user (admin1) and set up certificate based auth. I’ll be using Secure FTP/SFTP content up to the server as needed. Please note, I have disabled ROOT as well from my SSH config. My issue is that I don’t want FTP but rather ONLY Secure FTP/SFTP but I cannot upload with this user using a GUI SFTP client like Filezilla or WinSCP.

My current file permissions and ownership are Ubuntu server defaults of 755 and www-data:www-data.

Problem:
I try to upload via SFTP and it says I don’t have permission to do so. Yes, this make sense but I’m not sure how to fix it without having too lax a permission set.

Question(s):
What are the proper file permissions and ownership I must set to allow upload to /var/www/html without compromising the security of my server?

Is there a way that uploaded files to /var/www/html can have the proper owner of the directory in which they are loaded (www-data:www-data)?

I’ve tried to set /var/www/html to 775 and add the non-root user admin1 to the var-www group. Is that correct? I’d appreciate any help.

Thanks!