Your choice of the "best" UQ is really a personal decision. The only "problem" I see with full-size UQs is the bulk of the packed quilt as compared the packed bulk of a partial UQ. For temps down into the 20s my favorite is the Crow's Nest (3/4 length) UQ from Stormcrow at HammockGear. You'll need to supplement that with a pad of some sort for your lower legs and feet, but there are many candidates for that function ranging from seat pads to Evazote foam to CCF.
I prefer the 3/4 length UQ as my "best" compromise between coverage, weight and packed bulk.