Cogs are the same width but there's a fractional difference in spacer width. For best results get a 7 speed cassette ( preferably a racey one with a 28 tooth low gear ), slap in a 7 or 8 speed spacer behind it ( it don't matter with just one ) and bung on a 32 tooth cog. Job's a goodun'! 11-32 eight speed. Nice.
Looking at it from a designer w*nky point of view - Ive never been a fan of the Pauls clamps Dura-ace option. It cant be that difficult to produce some really nice svelte thumbies. Machines, trick, minimal....etc.
Give me a CNC machine and a BBC micro and a needle file and I'll have a set knocked up soon enuff.....