i have dr30, s12, and z31 companion flanges, drive cups/flanges and rear arms.
and also 610(so im guessing 510 as well) arms, flanges and stubs.
the s12 turbo and non turbo are all the big spline type, and all have 3X2 pattern, with 4 stud wheels.
the z31's all have the big spline, but non turbo's are 3X2 comp. flanges and 4 stud wheels.
the z31 turbo's are 4X1 comp. flanges and 5 stud wheels.
i used z31 5 stud stubs, companion flanges and 4X1 flanges to convert my s12 to 5 stud. the arms in fact appear identical.
all the "big" type stub axles run a larger inside diameter bearing on the wheel end of the stub, but the outer is interchangeable with the 610/510 bearings.
the dr30 parts i have from a FJ20et sedan, have the small spline. these companion flanges fit the 610 stub axle.
the dr30 stub itself has the larger diameter outer bearing, so isnt a straight swap into the 610/510 rear arm.
i did some homework a couple of years ago on sourcing an outer bearing for the dr30 stub in the 610 arms.
i did find one, but the write up i did is/was on DOCNZ
in short, you "should" be able to run the dr30 stub axle, and companion flange in a 510/610 arm, if you change the outer bearing to
bearing part #?????? and change/modify the bearing spacer tube to suit. this will give you 3X2 companion flanges on the arm.
or you could run the dr30 drive cup straight on (the weaker) 510/610 stub. also giving 3X2 flanges.
NOTE: this is all from memory from quite a while ago sorry. could measure some bit up here if you want...