No offence but you guys have rocks in your heads if you're using zinc washers to space out brake callipers. Those washers aren't high tensile and you run the risk of them compressing then the bolts will eventually come loose. I've fitted those brakes to my Soarer and didn't need spacers - they're close but they fit fine.

Sorry to sound harsh but your brakes are your life and if you're not 100% sure what you're doing (and putting callipers on the wrong way would suggest that) then please get a mechanic to check your work.