snow wheels that aren't hub centric

[Lines Peter]

I just put a set of Blizzak's on my 4kq.  I had them mounted on some black
steel wheels (the robocop look).  I'm a bit concerned because the bore in
the center of the wheel is larger than the hub pilot diameter.  As far as I
know, most Audis and VWs rely on this wheel bore/hub pilot diameter to
properly center the wheel.  The wheel bolt holes in the wheel are
countersunk and I'm using the stock wheel bolts with tapered heads (I
checked for proper length with the new wheels).  So when I put the wheel on,
and tighten in a criss-cross pattern, the bolts pull the wheel in to a
"centered" position.  I've driven the car up to around 80mph and there isn't
any vibration to speak of.  So it appears that the wheels are truly
centered.  Should I be worried about the gap in the pilot diameters?  Does
this fit have a strength feature above and beyond the simple centering?  It
wouldn't be too hard to turn some spacers out of aluminum and fit them in
the gap.  Any advice or BTDT?  Thanks.

Peter Lines