A set of staggered Sperzels tuners and Earvana nuts together will not require any string tree (Strat straight peghead, 1-11/16" nut width, compound 10"-16" radius, SS6105 fretwire, works with both .009 and .010 string gauges). Trees were not needed with Graphtech graphite or Corian nuts either (factory installed by Warmoth) before I removed them to fit Earvana nuts.
One reason to avoid trees above and beyond cosmetic considerations is that they add an extra contact in the string path. With a tremolo, this has to impact on tuning stability whether you like it or not, even just a tiny bit. Better avoid them if you can, but include one with your order just in case you end up needing one.