I've made the jacket from thru-hiker's kit too, but baffled instead of sewn through. It required some thinking on how to assemble and fill it, but everything went well. It also used a bit more down, but I wanted a jacket for real cold.
The sizing seems good to me (I used the wider cut). The only problem is the really wide and relatively low collar. I wish I had measured it before I cut the fabrics, I'd modify it to fit better. As it is, it works well when layered over other cold-weather clothes, but when put just over some light layer, it doesn't seal the neck at all. If you decide to make the kit (I think it's cheaper than buying the materials separately), measure the pattern and check how it works for you.