Consider trying to control the sides rather than tapering. Use some bear balm or beard wax to get the sides to lay down, or you can try just using a blow dryer in the morning to blow downward and add a little hair spray if needed. It gets easier the longer the sides get as gravity starts pulling them down as well. The sides will look fuller and you will still have the tapered look.

My Beard Journey:  http://jefffsbeardboard.yuku.com/topic/25137/Finally-I-have-a-Beard
Beard and Bald Thread:  http://jefffsbeardboard.yuku.com/topic/27831/Beard-bald-head-shaved-head-or-buzzcut
Patchy Beard Success Stories:  http://jefffsbeardboard.yuku.com/topic/33742/Patchy-Beard-success-stories-Before-and-After-photos#.ViujbH7nuM8
Taming the Wild Mustache:  http://jefffsbeardboard.yuku.com/topic/30822/Taming-the-Wild-Stache#.Vj_Mh7erTIU