Something I've noticed with regular disposable butane lighters seems to pertain to this.  It seems that the flint gets smoothed from use in 1 direction.  by sppinning the whell the 'wrong' way a few times it seems to roughen  theflint up a little, and when struck 'normally' afterwards, i generally see more spraks.  I dont own a sparklite yet, so i cant say it works with them as well. Something to try for yourselves i suppose.
Dave