Last minute questions for UQ DIY

Getting ready to start cutting 1.1 ripstop for UQ. Everything present and accounted for on the project list. Darn these ole brains we have...you know, the over thinking, the second guessing, and did I mention logic (at least through our own eyes). Bottom line is, I am questioning the "down" I have. I have a couple KMart specials. I was playing around with Catsplat's spreadsheet and now all of a sudden I'm worried. Believe me, I'm no gram junkie by any means. But lets say I was shooting for something that could get be down to 20deg. Using the 550ish FP of the Kmart down (as others have said) seems to be pushing the weight up prity quick. I'm not worried about the actual wt but will it cause problems holding the UQ up properly against my hammock? Does it take just a little heavier suspension and Im good to go? I'm looking purely at functionality. I'm telling myself, "Just shut up and sew the darn thing", which is what I'm going to do now. Any feedback on quality verse quantity, functionality, and any other feedback, or drawbacks, of using this low budget down.

The quality of the down is somewhere around 550. You don't know till you open the pillow. I made a down UQ from a pillow and used 27oz along with 20% overstuff. My UQ weighs in at 38 oz total. Yeah it sucks weight wise, but it sure is warm.

If you don't use grosgrain, you can save a few oz.

My UQ fits just fine under my WBBB. No problems sealing gaps or anything. I use the Leighlo suspension system right now. I use 1/8 shock cord and it pulls up tight.