I'm building a TT bike from parts I've got lying around. I've got a nice Chorus 10spd crank and BB but the bikes going to run with Shimano 8spd bar end shifters and, of course, an 8spd cassette, chain and derailleurs. How much of a washer should I put between between the ring(s) and spider arms? Should I move the big ring out or the small ring in or should I split the difference with some thin washers and move them both? Do I need to space the rings at all? Should I split the difference and run a 9spd chain and forget the washers?