The Preview panel of #FontLabVI gives you a flexible look at your design changes. Customize the text, sizes, tracking, slant, add a blur to simulate poor vision and (new in FontLab VI 6.0.6) change the foreground and background color. Try FontLab VI at https://fontlab.com/VI | Fontlab

Interpolate along the time axis in FontLab VI: Click Record on the History panel, make some “extreme” changes, then use the History slider to get a slightly “toned down” version of your modifications that will be an interpolation between the recorded snapshot and the final state. Buy or try #FontLabVI at https://fontlab.com/VI | Fontlab