Would posting a couple of pictures of the different caps, with and without ground wires help? I have several ignitions of each CH type but not all are mounted at the moment.

The first picture is a Taurus 3.2 with a CH ignition using the Bosch Cap. FYI, the engine does not come equipped this way, but with the rubber cap and ground wire.

The second picture is with an older Brison 3.2 and the originally equipped ignition. Rubber cap and ground strap. You can see where Brison manufactured the engine with the head drilled and tapped to accept the ground strap. If you have a head that you want to drill to affix the strap, DO NOT DRILL THIS LOCATION! It's directly over the combustion chamber and a depth mistake will be an expensive disaster!

The fourth picture shows an "X" with a pencil pointing to it. This would be one of the acceptable places to drill a hole since there is nothing under it to be a problem. The next picture provides a side view of the open space under the top fin.

The easiest way to do the job would be to drill a small hole the size needed, run a short #4 or #6 screw (depending on the size of the wire lug you use) from the top, and secure under the fin with a flat washer and flat hex nut. Use some blue Locktite on the hex nut, making sure that you do not get Locktite under the lug for the grounding strap, thereby maintaining a good ground contact. Take your time and things will go well.