At about 1/4", the spark should be thick and blue. I would worry if it was thin and orange at that gap. At least, every FC I have tested for spark showed a nice thick arc at that distance. 1st gens tend to have a much weaker spark.
To the original poster, the only way to test properly is with a spark tester. Not a timing light, not a jumper cable, etc. A spark tester is basically a spark plug with a slightly wider gap and an alligator clip connected to the ground. You clip the plug to the engine, connect the coil, and then start. You can now directly observe the spak. Thick and blue, with a defined "snapping" sound.