I have made 2 quilts out of primaloft sport. One using 3oz with a total weigh of 16oz. and a 2- 3oz layer one (one layer quilted to top fabric and other offset quilted to bottom fabric and with draft stopper wings) weighing 23oz. I have used the heavy one down to 30 (with wool socks) and was still toasty.
I have experienced similar performance with a quilt using 6oz previous generation PL One ... just slightly more clo/oz than current generation PL Sport.
Details of most recent usage (just this weekend):
* Shelter: TarpTent RainShadow 2, with floor, no bivy.
* Site info: unfrozen ground with a couple inches of pine needle duff on the surface. Under a not too dense pine canopy.
* Sleeping gear was 6oz/yd quilt on an old, old std wt thermarest, balaclava made with same PL One as the quilt.
* clothing worn: down socks, REI Sahara pants, short sleeve T shirt and a long sleeve BSA scout shirt, hooded unlined nylon wind breaker, MH powerstretch gloves
Friday night: temp started at about 40*F and bottomed out at 25*F for several hours, no wind. I was neither cold nor toasty ... about just right. I did have to pay a bit of attention to carefully positioning the quilt after rolling over.
Saturday night: temp was more or less constant in the 32*F-35*F range. Light and wet snow falling, approx 10MPH wind. Very comfortable.
Have had similar experiences other times in that temp range.