Effect of Dew Shield Length on Dew Prevention

Trying to find a length for a dew shield that prevents dew from forming and is not too sensitive to wind. I've created two shorter-length dew shields: one that is 7.5" longer than the scope and one that is only 3" longer. The stock Astrozap dew shield is 13" longer than the OTA. So far, the dew prevention objective is satisfied. Just hoping the 3"-dew shield isn't as sensitive to wind.