A timely reminder to actually go to the back shed and measure mine instead of using memory, mines old and ever more fallable!
So mine comes in at 4.5mm for the inner to middle and there is no spacer to web for the middle. On some Shimano docs there are two types of spacer , a thicker one for inner to middle and a thinner one for middle to spider web. So as ever there a variations upon a theme out there!