I'll get out one of my spare disc hubs and measure it.... I had some drum struts/hubs that I tossed out too... gonna kick myself if that would have been the go...

Thanks for the idea/advice.

On another tangent, I measured the thickness of some newer (97 ish) Camaro disc hats and they were only 3 mm! These were like 11" rotors too at least. The S13 discs are 8mm thick in the hat. Got me thinking about thinning them out some and cutting back the surface of the hub a little, like 4mm hat thickness and 3mm off the hub, then just raise the front a tad, but I'm not too sure about the safety.

Oh yeah the inserts I'm running are KYB from Matsuoka. 100mm shortened housings (the late ute disc strut housings are longer than the drum ones).