
I'm not sure those 'BIMECC' ones are the answer aye, theres no way that in relation to the 17mm nut those tapers are dia.29mm (refer to picture of OE nut, page1), i'd say you may as well use the subie nuts as use them.
You will also see on the picture of the OE nut that it has a groove around it, the inside (hub side) of this groove is the conical part of the taper, which centers the wheel (they are not hub-centric on a subie), then on the outside (nut side) of the groove is where the straight taper is, to tighten the nut. You can also see on the photo of the OE nut, that there is no residue on the ball seat portion of the nut in comparison to the straight taper, showing just how little pressure there is meant to be on the part of the wheel.
The ball seat part of the wheel isnt very thick at all, I wouldnt like to go down the ball seat adapter road...