Steve,?
Thanks for the advice. Tilting the saw arbor to 45 degrees improved access. Then I ran the belt over the scoring pully then the spring tensioned pulley below it, then back to the saw arbor & pulley. Still not enough slack, so while I reached thru the saw arbor space and pulled up on the tensioning pulley, my wife reached around the rear of the saw unit and slipped the belt over that pulley. Easy as pie. all I needed was that third hand!
Thanks everyone!
Nevin