How significant is the reduction in strength on the D-Lite version?

From : Don Stackhouse

For launching and flying, none, nada, zero. The spars in the 'D' and 'D-lite are identical. The dent resistance of the 'D-lite" is slightly lower because of the thinner wing skins, but not as much as we expected, it's not a big difference. If you're planning to land on rocks, gravel and yucca plants a lot, or if you tend to grab the wing hard during a hand catch (Joe and I usually try to grab the nose) you might want the 'D', otherwise I'd probably pick the 'D-lite' for the 1 ounce weight savings. The typical "contest arsenal" is a Wizard for windy days and a 'D-lite' for weaker conditions.

Don Stackhouse @ DJ Aerotech