Which synthetic insulated hooded parka for layering

i have some down outerwear by eddie bauer that i would consider a roomy cut. also i have a micropuff by patagonia that i would consider roomy. both of these may be options for you

I tried on the Eddie Bauer First Ascent Igniter Jacket the other day. It’s on sale right now for $129 to $149 and has regular and tall sizes up to XXL. Advertised weight (no size mentioned) is 19.7 ounces. Fill is 100 gram/meter Primaloft One (vs. 60 g/m insulation on the cocoon 60). The hood is very big to go over a helmet but adjusts down very nicely. Arms have a bend at the elbow and overall the jacket seemed very well designed. One note is there is a cord lock on the back of the hood which would be a problem if you’re going to sleep wearing it. I decided I wanted a warmer, more compressible belay parka so went with a down jacket instead.

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Hmm. . . I can layer a Medium Pro Parka over a Large Montbell Alpine Light + a Large MB UL Down Inner jacket. Plenty of room in the chest, but oddly, the sleeves don't seem to have proportionate volume. In that combo there's definitely a bit of compression in the sleeves, whereas the chest has room for another layer.

Also wrt the Pro Parka, the available reviews are accurate when they say it is a short jacket. The hemline just touches the top of my belt loops. The sleeves are so long that there aren't any riding up issues if I reach over my head, but despite the dropped rear hem, there is exposure when I bend at the waist.

Very warm parka though. Walking around the city, (my only chance to try it out so far) I was comfortable in typical day wear, (undershirt, long sleeve shirt) in 20F temps with 10F wind chill.