I'm in a similar boat as you. My primary shelter is a six moon designs lunar solo, which at 23 oz is pretty close to your contrail. I've looked at various tarp combinations, and it's pretty hard to come up with something significantly lighter without adding quite a bit of a fiddle factor and decrease in comfort. At the very extreme, I could come up with a shelter system in the 12-16 oz area (with full bug protection), but that's only a weight savings of 7-11 oz, which I'm hardly even going to feel on my back. I'd be adding quite a bit of fiddle factor/complication from using separate components (tarp/bivy, or tarp/groundcloth/bugnet), plus the combination is hardly going to be as comfortable as my lunar solo.
So I've more or less given up on the idea of tarping, at least when bugs are out. I don't really feel like I'm missing out on tarping with regards to being closer to nature either, since the lunar solo is pretty airy, and when opened up feels practically like a tarp in a lean to setup with it's big side entrance.