Anyone have these or tried them... The Dia Compe Gran Compe handlebars ?

Dia-Compe Gran Compe Track Handlebars: Track style alloy handle with 26.0mm clamp. Available in three colours. 38 or 40 cm widths 38cm - 330g 40cm - 335g

Does anyone know if these bars are perfectly tubular symmetrically or do they slope from the centre ? I wanted to know what brakes clamps they might fit - 23.8,24 etc... or only 26mm.

Many thanks,