Aloha George,
If you shorten the rod under the bonnet, you increase the amount of pedal travel before the rod engages the clutch master cylinder. Under the car, detach the return spring between the clutch operating arm and slave cylinder. The slave cylinder rod should be adjusted so that there is some play in it, about a quarter inch as I recall. If you can not move the slave cylinder rod back and forth by hand, it needs to be shortened. If the rod is to long, it moves the throughout bearing against clutch and will result in premature wear.
I had a problem adjusting my clutch pedal in the past. The root of the problem was the hole in the pedal that connects the master cylinder operating rod clevis. Over the years this round hole became an elongated slot. Welding up the slot and re drilling the hole solved the problem.
Safety Fast,
Dave