Changing the belts every 100K miles means this tool would pretty much sit in the drawer for almost it's entire life.
I got a set of GL-series ('Wing motor) cam-pulley locking pliers many years ago as a Christmas gift. They're my go-to for situations like this, and I've changed a number of belts on both my bikes and those of friends.
I'd find a buddy with one in his or her toolbox and buy him or her a nice dinner or beverage assortment of their choice for the loan of the tool and an extra set of hands.