How to set ftp (of sftp) default umask

[g3n]

The Dev team here at the office are developing a website, i want to change the permissions on the /var/www/html dir to make it writable by the group (in this case the groups is _elimon_) so i changed the group owner of all the html dir to elimon, and changed the permissions to 774 to all the files, now, i want to give them FTP or SFTP access, but as they arent sysadmins they dont want to fight with the permission when they upload, so i wanted to change the umask or something of the sftp to make automatically all upload 774 on its perms and 775 if they are directories, how can i do it?

I want this perms on the files:
-rwxrwxr-t 1 root elimon 1778 Jun 5 19:36 temporalmarco.php
drwxrwxr-x 2 g3n elimon 4096 Jun 11 17:29 test

for files and for dirs respectively
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