A 59cm Angus and and a 57cm Jamis Sputnik match up pretty closely as far as fit. Since their geometry is different, the Angus will have more precise (twitchier) handling though.

Edit: There is also an error on the IRO website for the standover height of the 59cm Angus. If you click on framesets, then Angus, he lists the standover height for a 59cm Angus as 33". Under the specifications heading he gives the standover as 32" for the 59cm Angus. The correct one is 32" as far as I can tell.

I sent Tony a message about the error a month or two ago, but he must not have gotten it.