I use bike inner tubes as well for my titebond 3 glue-ups. Bike inner tubes come is different sizes. Obviously in shorter and longer lengths, depending on the tire size. But racing bikes have narrower tires and thus narrower inner tubes. Most common tires are 1 3/8" x 1 5/8" in diameter. Myself, I cut these in half lengthwise, using a pair of scissors. If you don't cut them in half, I personally find them too stiff and difficult to stretch to do the glue up. A half tube is just elastic enough to easily stretch it, yet apply plenty of pressure on the laminations. However, I'm convinced a whole inner tube will work as well.
One inner tube is enough to do a glue up (as long as you cut it in two strips). But myself I prefer to wrap the glue-up twice: once from top to bottom and once from bottom to top. The inner tube wraps are then crossing over, which applies a more even pressure than wrapping once. The pressure sides level out, if you know what I mean. If you want to wrap the glue-up twice, you'll need about three half inner tube strips. I recommend to start with one strip and overlap the next one, by just going over the loose end. I don't like one long string of inner tube strips all tied together, because it is less easy to manoeuvre and creates knots at the junctions which can get into the way when you want to clamp the glue-up into a form such as reflex(/deflex).
