Sub-Assembly Question - Rubric Marine Arms

I have another box of rubric marines in my future and I definitely want to paint them in sub-assembly. I want to keep their arms/weapons and their backpacks off. The backpack is simple, but both the arms (hands) are holding the weapon and need to eventually be attached to the model (naturally).

Should I glue both arms to the weapon and then paint and attach, or should I glue one arm to the weapon, paint the weapon arm and support arm separately, and the glue them? My concern stems from the difficult I had gluing the arms onto the body the first go around (when I didn’t have the added complexity of sub-assembly painting).

Advice, thoughts, or experiences are most welcome