i'm gearing up to build an top quilt . designed to be in the 40-30degree range. thinking that tubes will be down filled 1.2"high and 3.5 wide.. baffels running ina cross the torso direction. the whole quilt will be aprox 10-15% over filled. now as i visualze this, the over fill will "blosson" the tubes and the result will be that the designed length will shorten. being that this is my first attempt at working with down, i'm a bit unsure that the shrinkage is something that must be addressed while in the design stage, if so, what kinda factor should i plug into this project.... or am i over thinking the this?