I would go for upholstery webbing pliers - the webbing is gripped in the toothed jaw, and the bent section acts as a fulcrum, allowing the webbing to be tensioned with one hand whilst being tacked in place with the other...
Cobblers (shoemakers) use a similar version but with a much narrower jaw, often with a built in hammer head - the technique is similar, but once stretched over the last the leather is held in place by the hand, and then the pliers used as a hammer to tack it in place...