To refer back to "Old'sCool' post the Stoner and the Hermco are not the same mold. To compare look at the bracket on KMoose's and Jnamowitz's bracket, the dive platform is much higher on the Stoner than the Hermco. The 4 1/2" number mentioned by Frizz is a good place to start.
Post #5 below shows the Hermco bracket's dive platform difference, compared to the link I sent yesterday.
http://www.classicseacraft.com/commu...ad.php?t=30331
One of those measure twice, three times.....or more.