I just bought the Kool Stop Continentals which do not offer a rounded spacer for toe in. I had TERRIBLE brake squeal esp. in the front. I did everything short of taking a wrench & bending the caliper arms. My understanding is that these side pull calipers are more flexy & sometimes the only solution, short of getting new brakes entirely, is different pads.

I ended dear up with Cane Creek "Grey Matter" 4-pack for $8 at Universal Cycles. No squealing and stop well.