I just realized that there is a new feature that actually allows you to program in crescendos and diminuendos. It's GREAT!
If you haven't tried it, the way it works is that you highlight the measure(s) over which you want the change in dynamics to happen and then you select either "cresc." or "dim." from the "Lines" menu. Make sure to put a dynamic marking at the point where you want the crescendo or diminuendo to end. You can increase or decrease the distance over which the change happens either by selecting the marking and pressing Shift-arrow key (left or right), or by clicking on the little square and dragging it to where you want it.
This makes a huge difference in the quality of the playback so, thank-you to everyone who helped develop this.