One of the issues with CS-130 is it really doesn't reflect the real plane exactly.   Yes the Aux tanks are inboard of #2 and #3 Engines, Main tanks 1 and 2 are Left wing and Main Tanks 3 and 4 are right engine.

Typically the Aux tanks will hold 855 Gallons/5814 lbs, The Externals that hang under the wing between the engines will hold 1309 Gallons/8901lbs and the main tanks will be different on each wing..
#1 and #4 Will be 1222 Gals/8310 lbs
@2 and #3 will be 1126 Gals/7657 lbs

Aux tanks are not always used in the plane.  (CS C-130) For the Aux tanks to drain first is kinda intersting since each engine is directly tied to a main tank (with boost pump) and the aux tanks have to feed the manifold to get to repective engines.  my understanding is real plane you have to transfer fuel to the main tanks from the Aux tank and the same with externals they do not feed directly to the engines.   They are to supplement the Main tanks.