I think what you need to remember is original BRM's have a 5mm offset and the Burners on your NOS '67
will be 42mm......so, taking into account that the burners are 1/2" wider the should still sit 43mm further in than the berms so if you use them with short axles you will need to use spacers to clear the spring plates and fit the caps. My calculations might be out, why they can't just use backspace rather than offset the world would be a better place
Here's mine with 67 axles, 205/60's and 35mm offset wheels