In other experiments, I tested interchangeability between the two kits, using the numbers in the instruction booklet for sisters and the body number from the Retributor instructions.
I tested the multimelta arms, but all looked similar for each body.
A Retributor guns fit:
B retributor guns:
I couldn't figure out sister 10, as her knee blocks the multimelta from fitting either arm for me.
1 is the superior. 2 just explaining the many heads and helmets. 3 the imagifier.
I feel this deserves a sticky.