If the Sidis were new when bought in 2000-2005, they will likely not work with clips/straps even if the OP goes with the Yellow Jersey cleat adapter. The velcro straps and such will make getting into/out of the clip/strap combo iffy at best. If one wants to use vintage pedals with clips and straps, it's best to use the shoes designed specifically for use with them.

Concur that Sidi used at least 3 different cleat types in the vintage era before the Look pattern became standardized.

DD