I found two original rusty Clips, cost me a buck at the junk yard, and found that it is almost identical to the Transmission Clip; the width is identical as is one end, it's the Vacuum Line end that needs to be modified. To that end, I went to the hardware store and bought two steel rods; one the diameter of the Vacuum Line and the other the Diameter of the Fuel Line.
I've not been able to do anything for a while but hopefully soon will get a chance to weld the rods together (side-by-side) which will give me the form I need and then bend one end of the Transmission Clip to the smaller Vacuum Line size. I haven't decided yet how to approach the extra length this creates and the sharp bend at the end but I purchased several Transmission Clips to experiment with. I also plan to use my heat gun instead of a torch to make the metal easier to bend and which I hope will preserve the finish.
The Valve Cover Clip I don't have an answer for at this point but will look into it. My cars have been '65's, so didn't need it.
I'll let you know how it turns out, pictures, etc.
Ray