@cgrifter I am definitely not an expert on rigging, so take this with a grain of salt, but two things after looking at the pictures. Are the upper arm bones parented to the clavicle. It looks like they might be in your images and I don’t think that is common practice. Clearing the parent might get you cleaner shoulder deformations. Also I think the bone joints normally rotate toward the z axis, so you will want to adjust the roll such that the z axis points toward the joint creases (like the elbow pit, it looks like the z axis comes out the side of your elbow). Also check to see if “Preserve volume” is checked in the armature deform modifier. I think it is off by default and that may also help. Again, not real solid on my rigging skills so if this is useless, sorry for wasting your time, but I hope it’s helpful.
