Optitrack retarget remap and offset bones (4-27)

Hi everyone. We have an optitrack system and have a live character driving a character asset in UE4.
The issue is the sizing of the actor on our mocap stage vs the size of the cg character. When we use the Optitack Live link Plugin we can connect our cg character without issue, however the scaling of the CG character is warped and looks very different from the original size.

I understand UE does not retarget in the way Motionbuilder does out of the box, and am wondering how I can get into the Animation Blueprint and add logic / nodes to account for and manage the offset between mocap actor and cg character.

Is there any resource on this, or are there any nodes anyone could point me to to begin working out a solution for this process?

Thanks so much!

Adam