Of the four you posted, the second one is probably the best value. Buckle is of the more-or-less correct style, and the band is an OEM Omega replacement. However, 11/16" is equivalent to 17.5mm metric and is probably the wrong size for your watch. I think yours would take a 16mm or 5/8" band.
However, you could use the buckle (probably 16mm) on a non-tapered band for this watch and save the Omega band for when you buy an 18mm lug width watch like a Seamaster or Constellation from the 1950's.
Take care,
gatorcpa
Edited by a mod Jun 1, 2023