I would perhaps go to the next step and figure out what metric size you need and stick to that. Someone should make metric parts of these that will fit and work for the long haul.
So there are two options here, that I can see.
7/16" may be an odd-ball size, but the links provided may get you on the hunt. The first link is intended to fit -into- the spherical bearing (that's not technically a heim or rod end). It is easier to install, offers more misalignment (which you may or may not need) and will effectively reduce the bolt requirement down to something like a 3/8". Which is likely adequate for this application.
http://www.polyperformance.com/High-Misalignment-SpacersOption 2 is more of a flare-fit (for lack of a better term) to the spherical bearing, it offers less misalignment, it's a little more cumbersome to install, but it allows you to keep a slightly larger bolt. You will want the spacer to fit into the bearing like a flare, to keep the bolt and bearing concentric.
http://www.polyperformance.com/Misalignment-Spacershttp://www.ballisticfabrication.com/High-Misalignment-_c_81-2.htmlThe Poly Performance link is generally playing with bigger parts for off-road use. 1/2"+. So you may need to search out a more car-based, or even UTV-based site for smaller parts.
As mentioned, if it's metric, stay metric. Do not try to make SAE/Imperial parts work without at least having the surface touching the bearing be metric.
