5mil spacer on 5 lug conversion Options

[Blown59]

If someone could educate me, it would be greatly appreciated. Ive done my CV shaft conversion for the 5 lug. My setup is this... 914 inner CV, 914 shaft, 4mil grind on the outer spline end, 944 CV, 944 stub, boxter wheel hub. I'm reading that I need a 5 mil spacer in one of two, possibly both locations. I dont see this as being necessary. One image shows a spacer on the stub placed where the stub shaft enters the bearing race and mates to the hub shaft... I dont see how this could possibly work. Second, I see information calling for the spacer to slide on the back of the hub stub for shaft input. To me, this would seem to prevent the stub shaft from fully seating, leaving a 5 mil gap inside the bearing race (maybe this is where the "other 5 mil spacer is supposed to go?).

This then brings me to my last question... If your space everything out 5 mil, arent you loosing 5 mil of spline engagement? I'm using boxter rear bearings as I understand they are identical in size to the 914, just actually better (more bearings?). As I line everything up, prior to assembly everything seems to fit as it should. Stub and hub join properly and sit flush. Bearing is correct size for distance between hub/stub. Plenty of engagement/support from sub/hub on inner bearing race wall. It doesnt appear there would be any engagement on the outter race wall from the sub or hub. And it doeant appear that the 914 sub engaged the bearing except on the inner race wall.

So, I dont see where the need is for the 5 mil spacer. I dont want to ruin bearings and have to disassemble if it doesnt function properly or worse case damage something in my attempt to drive it as is.

If I'm wrong or am not fully understanding something, can someone please correct my ignorance or lack of understanding? Or is it possible this may be an alternative setup to the 911 hubs without a ton of "extra bits"??