Awesome, you really know all the tricks. If I wasn't so impatient...
I just pasted in the following into the IR_Segment_TrussLarge_5m00/part.cfg. Gave me the nodes I was after, I have to remember I did it though - update and its gone.
node_stack_right = 0.1823258, 0, 0, 1, 0, 0, 0
node_stack_left = -0.1823258, 0, 0, -1, 0, 0, 0
node_stack_back = 0, 0, 0.1823258, 0, 0, 1, 0
node_stack_front = 0, 0,-0.1823258, 0, 0, -1, 0
If I hadn't spent a few hours designing, testing and then building this on the moon (Extraplanetary Launchpad), I'd go back and do it properly...