Spokes don't stretch unless they're stressed beyond their elastic limits. Otherwise they lengthen and shorten like springs within their elastic range as the loads change. If your spokes stretched over time your wheels are too tight for the spoke you're using, and/or the stresses of use are taking the spokes beyond their design working capacity.

Assuming the same material, the ideal spoke tension is proportional to the cross-sectional area of the spoke, so a DT revolution might only be able to be tensioned about half as tight as a 14g plain gauge spoke. This is one of the reasons that I usually build high dish wheels using thinner spokes on the left flange.