Hey mate, not sure if this will help, but...
Got the TRX style rims on, with low, square profile BF Goodrich tyres on. they are 15's 195x50x15
They have magnesium wheel spacers, and I just drove the ute 2100 km without a worry with the wheels. I wouldnt worry too much about spacers being dangerous.
I took mine for a wheel balance and they used a bit of cardboard to centre the spacers after balancing the rims...
pretty technical stuff

The wheel nuts I am using are a long cylindrical type where half of the nut goes through the rim.