Chiming in on above questions and pretty much echo the previous responses.
Regarding weight, defo a toasty jacket for most regular winter weather areas. Has a nice heft to it, way more than a standard waxed cotton, but not for sub zero temps. Also, without a sweater underneath it would be fine in moderate cool weather without smoking you out.
Size wise, Im a 42/44 and I went with a 44, which works, but will probably swap for a 42 for a slimmer profile.