the yeti has draft stoppers on the ends only. there is no drawcord there, just the draft stopper to seal off any tiny gap that might otherwise be there right at the end-edge. there are none along the sides.
the problem is that since you lay diagonally, the uq needs to be cocked at a similar angle to get the best fit. the uq will want to right itself and go back to a straight-on/in-line fit. having a tight shockcord does a couple things. it applies signifigant tension to the quilt, this pulls the inner shell "tight" against the bottom of the hammock. this is what you want, the tighter the inner shell is to the hammock bottom the more efficient it will be (obviously to a point), but with minimal tension you're probably not gonna have the inner shell as flush to the hammock bottom as it could be. a secondary effect of tight shockcord is that this extra tension keeps the uq from migrating back into an in-line position (off you shoulder).
note, most of these observations are based on my experiences with the yeti these comments are more specific to that design but may be similar for similar designs. drastically different designs would be a less appropriate comparison, so alot depends on the design in question and this is why it's tough to make generalizations. even when discussing just full length uq's for example, the design of the quilt has alot to do with what kind of suspension works best. as far as full length goes, HG and JRB are different shapes and i'd expect different results if you rigged each with the exact same suspension. picking the exact suspension option that would work best is probably best done on a case by case basis depending on what quilt you're using. you'd hope the mfg has already done the necessary testing and picked the most appropriate suspension for their particular quilt design.