A good tip for making spacers is to buy a bearing with the same internal and width measurements that you want - the outer size is not important - and then cut off the outer race to leave you with just the inner race, and a perfect spacer! You can pick bearings up for a couple of quid each, and you know they're made of the right material too.
I did this when removing the speedo drive on my 748 and fitting a TransLogic dash.
I'd rather die peacefully in my sleep like my Grandfather, than screaming in terror like his passengers.- Jim Harkins