Looking for one of these babies...

Not sure if a men's L or M would be better for me - I'm a tad, ahem, endowed on top and want to be able to layer a bit underneath. I tend to wear a men's LARGE jacket in Montbell's sizing, primarily to fit the waist over my hips. Arcteryx men's I wear a MEDIUM.

email jenmitol AT gmail DOT com
Thanks!!