I prefer rubber bands from bike tubes, and must say this works excellent althoug it`s kinda workout to tension a whole longbow to the form.
One day I`ll run a firehose system for sure but for few bows the rubber`s alright.
Using heatboxes the bands have another advantage- as most materials grow when heating up they even get shorter to follow the glue getting thiner trough the heat.

Joe. Lignostone is Beech wood that has been impregnated with an artificial resin and compressed with huge pressure. It becomes very heavy, about twice its original weight. Great compression and tension strength. It looks like a dark Rosewood. Here in Norway it was used as "wearing"edges on wood skies before they started using glassfiber and steel. I use it as reinforcement beams in bow risers . I have also used it to make RD bows, two or three thin prallels and a taper with a glued in handle. Like a glass bow without glass. I may sound pretentious, but I do not know of others who have done the same. I have tried it in combination with strong woods like Hickory or Ash and the bows did break, was like the Lignostone was kind of overpowering the woods no matter where I positioned it in the bow limb. Since it is so heavy it is probably not the best bow laminate, but I like to try out things. The stuff that I have is about 40 years old and  I don't know If they make it anymore, could do a Google search, I guess. Bue--.