Character Sets for Posting

Tools - Global Options - Encoding Tab

Preferred character set
Select the character set to be used for posts. If there are no 8-bit characters, Gravity will use "us-ascii" 7-bit even if you specify a character set.
Content-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"

Send 8 bit characters
Specify if you want the article BODY posted 8 bit or 7 bit encoded. If you do not select 8 bit, Gravity will encode the message body as 7 bit Quoted Printable.
Send 8 bit chars in header lines
Specify if you want the article HEADERS posted 8 bit (Subject, From, etc). If you do not post 8 bit header lines, Gravity will encode the header characters 7 bit Quoted Printable.
Whether to post 7 bit or 8 bit is up to you. Some groups may have customs.
Most "standards" today recommend sending MIME encoded 7 bit headers.