my 0.02, standard beadheads make little differnce for weight compared to lead or tungsten, I tie a some nymphs wrapped in lead with a tungsten head for my "heavy flies", lead with standard bead (the ones i use are not actually for tying so they are pretty light) for my medium flies, and just a straight bead head for regular or unweighted nymphs...however most times I use split to control my drift, unless its in shallow or slow moving water where fish can get a better look..then i use weight nymphs to try for a more natural drift..