HELP! Elbow FABRIK/Bone transform correction

Hi all,
I searched the depths of internet that I haven’t even known existed until recently… seen things… Horrible things! But I haven’t found a solution for my problem - so I will ask the community.

The problem:
I am using a first person animations for weapons on a 3rd person full body character. I managed to blend poses correctly for the spine and shoulders. made some aim offsets (procedurally) and it works as intended… However because of the nature of first person animations the elbows of the character are extremly close to the body, and overlap it at some cases. it just looks rediculous.

So what I need:
There is a simple way to fix the left hand position on weapon with FABRIK node and I bet that there is a simple solution for posing elbows to bend to sides of the body jsut a little bit. a bone transform of upper arm by 30 degree would be great… but I wish to keep the position of hand bone in place. I thought of 2 fabrik nodes…
When I use tranform modify bone for upper arm twisty - it breaks. for upper arm - it breaks.
For the first node the Upperarm_R modify with component space and rotation modification added to existing seems to do the best work… now how to reposition the hand_r ?