In using Sock It To Me (again, similar to Cascade Fixation), I tried to compensate for the springyness in my first footie and overcompensated - it was a little too loosely knit (and will remain that way as I was too lazy to frog ) But for my second footie, as I didn't want to have to fix loose-ladders and holey parts again, I knit at a 'normal' tension and it came out looking...normal! Not too stretched and not loose. I only had to slightly fix the ladder between 2 needles. I did not pull as tightly as I should have between two of my needles and I still got that ladder effect. Next time, I'm treat the yarn entirely as a 'regular' yarn (pulling snuggly between dpns) and seeing what happens. I'm sure it'll turn out just fine.
Be not afraid - I really like this yarn now. In the pattern I was using, it cautions that this yarn will shrink a little, but I haven't washed yet and no, I didn't do a swatch. I figured since my feet are slightly smaller than Mom's I could always wear them if they shrunk too small for her.