I have now measure the OEM studs length protrusion beyond the spacer, and it will indeed NOT fit with anything less than a 20mm spacer (stock wheels and stock studs).
The studs protrude very nearly 10.83mm beyond my 20mm spacers, and the pocket depth on my OEM rims is very nearly 12.42mm - leaving only 1.59mm of clearance (0.063")
Anything less than a 20mm spacer would need the have the studs trimmed shorter, or replaced with Ionger studs meant for spacers that do not have integrated studs