Spearing the hole, and getting the threads of the cable cap to mate with the carb casting is difficult, especially with a stock choke cable elbow disrupting the process.
Two major obstacles arise:
first, the threads are TAPERED; getting the cap axis perpendicular to the female threads cut in the carb ain't always easy or obvious.
Next, with the carb mounted, there's VERY LITTLE room to work with; virtually impossible to get a standard 12 mm open-end wrench on the cable cap flats (don't remember if the aluminum aftermarket cap has flats, or merely a knurled surface). BTW, for a few dollars extra, you can get a BRASS (vs. an aluminum) cap; no operational advantage, aesthetic only!
Well, I've described the problems, where are the solutions? Anything to get more access to mate the cable to the carb; extreme case: dismount the carb and fasten the cable. And then, there's the matter of special tools . . . Normk knows of a custom slotted socket wrench capable of slipping over the cable and engaging the cap. Some have cleverly bent the ends of 12 mm open-end wrenches to do this honor.
What did I do? Frustrated with the plastic cable cap for years, I, too, bought a metal cap from Stead engineering. Then, I bought a Drag Specialties shorty choke cable intended for Harleys.
I shortened the cable stem (using a Moto Tool cut-off wheel, the knob does not unscrew from the Drag Specialies product). I then threaded the shortened end and installed a replacement knob. I drilled a hole in the kickstand switch plastic cover and mounted the cable there.
Now, no pesky cable elbow impedes my progress; the shorty cable feeds straight into the carb, facilitating thread mating between the cable cap and the carb body. The choke knob is easily accessible (unlike those mating directly to the carb), and since I trimmed the cable stem, no interference with the rider's legs, or the ground, in the event of an upset.
The Drag Specialties cable has tension adjustment, facilitating holding the "choke" (starting enricher) ON in various magnitudes.
I'll try to post some images.
The Drag Specialties cable and knob will fit, as is, out of the box. However, I wanted a shorter cable stem and went to the effort of cutting the original, threading the stub, and inserting the knob shown above. No need to post pictures of a MotoTool and cutoff wheel, or a tap-and-die set!