I've not really played with beads before, so haven't paid them much attention. For the Swap I'm tying two Von Shucks for each person, mainly so that the "hoarders" might actually fish with an 'extra'. I'm tying with two different beads (OK, three or four, using up random beads), one a small glass bead, the other a 1/8th-inch brass one, to give you two different sink rates.
I pulled out my reloading scale- a bead can make a real difference in weight! The metal bead weighs more than 10 times the glass, is heavier than either the hook or the dressing, and is almost half the weight of the finished fly. The small glass bead, on the other hand, is not worth any consideration at all. The effect of weight is relative, and perhaps even a heavy Von Shuck is of no account in a given current or with whatever line/leader is on your reel; but in its own little world, the choice of bead makes a difference.
