FF Vireo as Stand Alone Half Bag

As a result of Moondog's enduring enthusiasm for this concept, and following a bit of research, I am considering trying the Vireo as a longish half bag. For me, the Vireo seems to offer definite benefits over the PHD half bags and the WM Tamarack, mainly being much slimmer.
I am not a believer in carrying additional clothing to compensate for an insufficiently warm bag. However, if I can save a bit of weight with my bag by wearing in the bag some of the clothes which I am already carrying, that could be a good thing.
I always have thermal top, 100 fleece, and a down jacket. The jacket is mainly for around camp and "just in case" wear. The fleece usually serves as part of my pillow, but I can probably deal with that if necessary.
The Vireo is available in two versions, the UL and the Nano, of which the Nano appears to have heavier, and presumably more robust, fabrics. Given that this will be used stand alone, with no liner, I think I would be happy to carry an extra 50 grams for the added durability.
Any thoughts ? Anyone ? Alternatives that I may have missed ?
And please don't introduce quilts to the discussion. I have tried long and hard to find any thing about quilts that suits me and my usage and have failed.
I don't want one 
I am not a believer in carrying additional clothing to compensate for an insufficiently warm bag. However, if I can save a bit of weight with my bag by wearing in the bag some of the clothes which I am already carrying, that could be a good thing.
I always have thermal top, 100 fleece, and a down jacket. The jacket is mainly for around camp and "just in case" wear. The fleece usually serves as part of my pillow, but I can probably deal with that if necessary.
The Vireo is available in two versions, the UL and the Nano, of which the Nano appears to have heavier, and presumably more robust, fabrics. Given that this will be used stand alone, with no liner, I think I would be happy to carry an extra 50 grams for the added durability.
Any thoughts ? Anyone ? Alternatives that I may have missed ?
And please don't introduce quilts to the discussion. I have tried long and hard to find any thing about quilts that suits me and my usage and have failed.

