My standard setup consists of a Uniqlo down parka, Dri Ducks rain suit and a lightweight, fairly tight fleece vest.
Got the down jacket on sale for 45 bucks, the Dri Ducks for twenty bucks and the fleece vest from a second hand store for a buck.
I haven't weighed the vest. The medium size Dri Ducks are 10.1 ounces and the down coat is under ten ounces.
The down coat is on the light side for an actual winter coat but works good for chill evenings and mornings, and is very comfortable to sleep in. With my balding pate the hood really helps hold the heat in. They also sell reasonably priced coats without a hood and vests. Ya might wanna give them a peak -
I stick with the fleece vest for those rainy days when I need extra torso insulation. I'm a skinny feller and get chilled easy, and I do not want to wear a down coat for wet weather work as that's asking for trouble!
For me, the lightweight down coat is strictly for around camp after I've stopped hiking and need more insulation and for sleeping in.
Now the Dri Ducks are really useful. They make a great pillow. The pants are also very comfortable pajama bottoms! Dri Ducks pants on my legs and that down coat on top and I can sleep comfortably in quite cold weather.
For sleeping, I find the loose "pajama" bottoms much warmer and more comfortable than skin tight long johns!
Of course, I'd never try this with non-breathable rain gear.
Of course I'll also wear a light, long sleeve, light colored synthetic shirt, these days usually an old dress shirt, and a felt cowboy hat. This combo of synthetic dress shirt, light fleece vest, UL down parka and breathable rain suit works for me for just about any three season mix.