The only reason for putting in an easement is so that the trains don't "jerk" when going into the curve. This can sometimes be referred to as the "Lionel trains effect" because that what Lionel trains do when they go around a curve.
If you are a picker of nits, then an easement might look nice. Model Railroader did an issue decades ago that included templates for easements of different radii. However, it's a simple matter of starting about 12" - 18" up on the straight track and offsetting this track about 1/8" - 3/16" (depending on the radius) before the curve. You then "blend" the 12" - 18" of track into the curve so that it doesn't look as if your straight track immediately jerks into your curve.
Bob M.
PS - Love that benchwork with the styrofoam!
