You might want to review Help, Message formatting and Margin section again. Set window with does affect and limit available line length as does set size of Editor font also.

Message width  This setting controls how wide the column of text you type in your message should be. The default setting is 145mm or 5.71 inches, based on a typeface of Arial 10 point. This will result in a column of text approximately 76 characters wide, which should be readable by anyone. If you increase the size of your typeface, you may also need to increase the message width, since otherwise your lines will become shorter and shorter. Similarly, if you use a smaller typeface, you should make the message width narrower to keep the lines within a reasonable length. Experiment with these settings until you find a message width that youfind comfortable and which produces messages your correspondents have no trouble reading. As a general rule of thumb, you should choose settings that result in the lines in your message being between 70 and 80 characters long.

Also refer to the section earlier about side effects of disabling  all text formatting which imposes other restrictions when used.

I have my PMail Preferences and Features/Out Going/Tabs and margins/Message width 24.02/ <Tab> width 0.51/Units Inches

Right margin for Ctrl+J reformatting command 139 (characters)

 Font Arial Black/Bold Size 14 and still the width of the message being created is only 45 characters wide.  There should be a selection to allow Screen Width so our messages are the full screen not just several pages of only 44,45 or 50 characters wide.  I have set the character width from 70 to 145 and nothing seems to allow it to expand.  Is there a special Font that could be used to expand this or just not possible?

 Have set the Font down to 7 Arial Black Bold and managed to get out to 83 characters, seems there is a limit on the width is fiscal.  With Font size of 10 there are only 44 characters.