How thin can a baffled down quilt be?

I'm considering the idea of making a lightweight summer quilt using baffled, down construction. The question is, how thin can I make the baffles and still be practical?

I'm considering 1" tall baffles and fill them to an average thickness of 1.5" Also, my theory is that the baffle spacing is a relationship to the baffle height. In other words, the taller the baffles – the further apart they should be. The short 1" baffles would then require a spacing of about 3"-4" apart.

I know that I could do the sewn-thru method but, the idea of non-uniform insulation just doesn't sit well with me.

Does anyone have experience with making a very thin, baffled down garment?