Thank you Metalstudman1, with your input I was able to go out this afternoon and make the mounting for my jackshaft. It still needs the adjustment slots but I'm closer now. I'll try and place two pictures at the end of this message. Once you discribed the set up, DAH! What was I finding so hard? I can chalk it up to age, I'm not the sharpest tack in the box anymore. (If I ever was) :-)
Now I must find bushings and sprockets to fit axle/jackshaft/disk brake. The brake was a good thought, I'll be sure to install one. I will use the belt web site info for sure. Now I'm going to try and include 2 pictures.
You'll see I just extended the rails and will put lateral support in later. It was like an epiphany when I read you post,, so easy.
RDomke@Comcast.Net