I would like to get a copy of the Sterling PT - 19 kit # M-9, 21 inch control liner for .020 / .049 power. Can any one help?

Hi Steve, hope you're well. I can't help with the Sterling plan, but here's a link to an Earl Stahl plan of the PT 19, 23" span, might be of some help anyway.
http://www.theplanpage.com/esp/pt19.htm
John from Sydney.