Check out the reader reviews and the articles here if you haven't already. Lots of people agree on a little overfill only to prevent shifting of the down. 2oz spread somewhat evenly was my pref, others might like most of it in the footbox.
As for fabric, I''ve got a different take: fabric performance trumps color performance. Just to be clear, 1.1 oz/yd2 ripstop is heavier than .9 oz/yd2 Pertex Quantum. (Sorry - it kind of reads to me like you're saying the other way around in your post. If not, my apologies!) Also, most if not all 1.1 ripstops are less breathable than .9 Pertex Quantum. Even Nunatak's .85 ripstop is ~slightly~ less breathable than PQ. But .85 (in blue) could be a better choice than PQ if you're willing to sacrafice some external moisture resistance, as well as an albeit miniscule amount of breathability, for the sun-drying factor.
If you're unsure, you could ask Tom to break down the fabrics on a spectrum of breathable v. resistant to external moisture.
Epic is far less breathable still, but the concept is the same: any compromise in breathability causes more internal condensation, requiring more 'sun-drying performance' to begin with.
I swear by my Vapr, definitely useful for the 'external' moisture control w/out itself hampering breathability. But it doesn't compensate for lack of breathability in the lower layers per se, tho it does add another temperature gradient which ~can~ move the dewpoint outward. But Epic shelled bags, for ex, kind of defeat the strengths of the Vapr bivy (over multiple nights anyway), esp if sleeping in damp clothes in cold weather when breathability of all layers is key. Anyway, in warmer temps and/or short trips these differences are hard to notice, but 30s and below for longer trips is another story in my experience, with any kit. Depends on your goals. Best of luck!