Hawthorne Silver Iris 15’ cutouts

Darrell's specs in the Wayback (orig SI, not Sterling) have 13.75 cutout & 15.25 OD with .28 hole dia and no bolt circle mention. If you look at Beta15CX info, it's 13.77" / 349.6mm & 15.15" / 384.8mm, respectively, with bolt circle dia 14.562" / 369.9mm. Always best to have drivers in-hand and verify.